9 * « 



111 






Modern Survey" 



IMONIALS. 



U.' S. Coast and Geodetic Survey, 

Sub Office, June 2, 1888. 



A N F) THEI1^ S * ^ nne > asking me to express an opinion of 
lent makers. 

^d to the business of Carl Bahsskopff, I have 

er of your workmanship upon the various 

_ TT T sted to your care that I have seen no reason 

Containing Useful Info' 

f.d novel devices you have fully conipre- 
ClVIL ENGINEER AND e intelligently supplied them. 

ery respectfully, 

George Davidson. 

together with San Francisco, May 14, 1888. 

establishment for the manufacture of 
•-> a rp k t /"X/^ T TIT ID 11 vvledge I have of your excellent appli- 

(^ A 1 ALVJLj U C AND r f nt thereof, especially as you have fur- 

rkmanship in the Transit purchased 

OF a since been constantly used in im- 

nous country, and I am informed by 

in every respect exceedingly ac- 

SCIENTIFIC INSTRUMl d: I am glad to express my 

mendation of your ability to 

Particularly those of the Civil Engineer and ^oTT^Thn , v f « E 

24, 1888. 



MADE by 



The A. Lietz Company, 



422 SACRAMENTO STREET, 
_ - San Francisco, California. 

T A 

581 *^ 

I I ( I PRICE, 50 CENTS. 

PUBLISHED BY THE COMPANY. 

All Rights Reserved. 



rny satis- 
jiueli time. 



H, 

iiigineer. 

) 4, 1888. 

the excel- 
;ht of you, 
.- the most 
deserve the 

sharp and 
:h superior 

consider it 

of A No. 1 
on. 

R0S., 

ngineers. 



\ 






TESTIMONIALS 



U. S. Coast and Geodetic Survey, 

Sub Office, June 2, 1888. 
A. Lietz Co., San Francisco, Cal. : 

Gentlemen— I have your note of 1st June, asking me to express an opinion of 
your character as Mathematical Instrument makers. 

For the six years since you succeeded to the business of Carl Rahsskopff, I have 
been so well satisfied with the character of your workmanship upon the various 
kinds of instruments which I have intrusted to your care that I have seen no reason 
whatever to make any change. 

In the matter of new instruments and novel devices you have fully compre- 
hended the wants of the observer and have intelligently supplied them. 

Very respectfully, 

George Davidson. 



San Francisco, May 14, 1888. 
A. Lietz Co., San Francisco: 

Gentlemen — My acquaintance with your establishment for the manufacture of 
Nautical and Field Instruments, and the knowledge I have of your excellent appli- 
ances for such work, prompts me to a statement thereof, especially as you have fur- 
nished me with a substantial proof of your workmanship in the Transit purchased 
of you some months ago. This instrument has since been constantly used in im- 
portant surveys in an extremely rough mountainous country, and I am informed by 
my son, who has been operating with it, that it is in every respect exceedingly ac- 
curate in all operations for which a Transit is designed. I am glad to express my 
satisfaction of its results and consider it a high recommendation of your ability to 
make superior instruments. 

' : Respectfully yours, 

Calvin Brown, C. E. 



Berkeley, Cal., May 24, 1888. 
A. Lietz Co., San Francisco, Cal.: 

Gentlemen— Having your Transit in use, I take pleasure in expressing my satis- 
faction. I am pleased particularly with the Tripod Coupling, it saving much time. 

Respectfully, 

R. E. Bush, 

Civil Engineer. 



San Jose, Cal., June 4, 1888. 
A. Lietz Co., San Francisco: 

Gentlemen — It is with great pleasure that we add our testimony to the excel- 
lency of your Instruments. The two Transits and one large Y-level bought of you, 
are in every respect as good and serviceable as the instruments made by the most 
reputed of eastern firms, and as a purely California or home production deserve the 
greatest credit. 

The graduations made on your own graduating machine are clear, sharp and 
exact, the glasses of the very best make and power, and the needles much superior 
to the general run of needles. 

Your Tripod Coupling is at once simple, effective and safe, and we consider it 
better than any other coupling used by other makers. 

We can but congratulate you upon your success in the production of A No. 1 
California made instrument, and heartily recommend you to the profession. 

Very truly yours, 

Hermann Bros., 
Surveyors and Civil Engineers. 



Candelaria, Nevada, March 20, 1893. 
A. Lietz Co., San Francisco: 

Dear Sirs — I am highly pleased with my Transit No. 254, made by •you, which 
I have been using constantly for over a year. It is thoroughly reliable, and I con- 
sider it one of the best in use. I have had occasion to use it a great deal in long lev- 
eling practice, and my limit of error per mile has never exceeded one-tenth of a foot. 
It is a combination of accuracy, strength and lightness, and I can-safely recommend 
the same in every particular to the engineering profession. 

Yours truly. , 

Johx G. Booker, 
U. S. Deputy Mineral Surveyor for Nevada. 



Lake Greeno, Cal., March 27, 1893. 
A. Lietz Co., San Francisco: 

Gentlemen — Over two years ago I purchased one of your 18-inch Y-levels. It 
has been in constant use ever since, sometimes subjected to very severe handling, 
and I desire to say that in over fifteen years' practice in the field, using instruments 
from most of the standard makers, yours is the peer of any in design, workmanship, 
action and all of the attributes of a first-class instrument. The ease of manipula- 
tion and constancy of adjustment are qualities possessed by it in a marked degree, 
and the improvements are just what are needed. 

In short, I would not exchange mine now for an instrument of the same grade 
from any other maker. I expect soon to lay aside all others and to use none but 
Lietz instruments in all branches of my field work covered by them. 

It is a great pleasure to me to show the good points of my level to my profes- 
sional brothers. 

Yours respectfully, 

P. M. Norboe, 

Civil Engineer. 

Juneau, Alaska, January 14, 1893. 
A. Lietz Co., San Francisco: 

Gentlemen — I take pleasure in stating that the Mountain Transit purchased from 
you and used the past season has proven excellent. The graduations are clean and 
sharp. In regard to accuracy of the graduation, reliability of instrument in its ad- 
justments — the tripod not only simple and safe,, but always rigid — and strength 
combined with lightness, it proves entirely satisfactory. 
Yours truly, 

Chas. W. Garside, 

U.S. Deputy Mineral Surveyor for 
Alaska, and Mining Engineer. 

Sax Jose, Cal., June 17, 1893. 
A. Lietz Co., San Francisco: 

Sirs — In regard to the Simplified Transit bought of you last Fall, permit me to 
say that I have used it continually since I have had it and am very much pleased 
with it. It is light, handy, easily kept in adjustment and very accurate. In short 
it is all you represented it to be. Will be pleased to recommend the instrument to 
any one. 

Very truly, N. C. Parker. 



Sax Francisco, January 5, 1893. 

In the autumn of last year I made all the surveys necessary for a proposed Cut-off 
of the Yuba River near Marysville, California, with one of the Lietz Simplified Tran- 
sits, and I have been surprised with how mncb accuracy field work can be done with 
these handy and light little instruments. The work had to be done rapidly and the 
stadia method was chosen. It gave me great pleasure to find out how accurately the 
work closed, both in angular and linear measure. 

An entire project was worked out for the Government from this survey. 

Otto Vox Geldlrx. 



MANUAL 

OF 

Modern Surveying Instruments 

AND THEIR USES, 

Containing Useful Information for the 
Civil Engineer and Surveyor. 

TOGETHER WITH A 

CATALOGUE and PRICE LIST 

OF 

SCIENTIFIC INSTRUMENTS, 
Particularly those of the Civil Engineer and Surveyor. 



The A. Lietz Company, 



422 SACRAMENTO STREET, 

San Francisco, California. 

rr or wasvv^ J 



PRICE, 50 CENTS. 

Published by the Company. 



> 7 ^vy 



K 



Notice 



fT^HIS Manual supersedes the former edition of our cat- 
alogue, and is carefully revised and corrected to date. 

The articles manufactured by this Company are 
quoted at prices consistent with the quality of workman- 
ship, and no deductions will be made. We endeavor to 
place before the public an equivalent of the very best that 
can be obtained in this country, without imitating in 
shape or design any make whatever, considering the Buff 
and Berger instrument the standard of excellence. 

Distant purchasers will please remit by check, money 
order, or registered letter. 

According to the rules of Wells, Fargo's Express Com- 
pany, a surveying instrument, carefully placed in its case 
and in a packing box, is shipped as merchandise and 
charged for accordingly. The customer should remember 
this when express charges are made, to avoid all error. 

Packing boxes are furnished by us at a nominal rate. 



n 



w 



p 



A" 



PREFACE 



"TTTE issue this book for the benefit of the engineering pro- 
fession. This statement is justified in every way. 
Comparatively few are aware that scientific instruments are 
made on the Pacific Coast, and if it were generally known, it 
would require considerable effort to remove the doubt, whether 
our home industry work could possibly compare with that of the 
Eastern maker. It is difficult to see why such disparaging opin- 
ions should exist, but, as they do, we have endeavored to remove 
that prejudice by publishing a careful description of what we 
are able to produce — not only that, but just how we produce it 
— so that the public may have that confidence which an earnest 
effort, honest labor and skilful handiwork deserves. We benefit 
the profession if we can accomplish this object. 

Considerable information has been published herewith. 
The details of every instrument are carefully enumerated, and 
the functions of every part minutely described, so that the little 
book really becomes a pocket companion for the engineer. 

We would advise our patrons not to undertake any difficult 
repairs or adjustments to an instrument without consulting this 
Manual, wherein every adjustment and make-shift repair has 
found special mention and careful consideration. Refer to the 
index, and look up the subject before undertaking anything 
that may lead to more serious trouble afterwards. 

The Manual is divided into four parts. 

Part I contains a full description of our establishment and 
its methods of working. 

Part II deals with the manufacture of Engineering Instru- 
ments, their uses, repair, adjustments and proper methods of 



IV 

handling them, so that they may retain their fine qualities for 
an indefinite time. 

Part III contains a number of professional papers, written 
by well-known men. They furnish considerable information 
of value, and we would ask you to give them your attention. 
The article on Stadia Surveying has been written for this 
Manual, and from it this method of measuring may be readily 
acquired by any surveyor. No expense has been spared to make 
these papers complete in every particular, including useful 
tables that cannot be had in any other book of this kind. 

Part IV has a full price list of every article manufactured 
and sold by the Company. The customer may find any infor- 
mation, and arrange his purchase to the money he may desire 
to spend. 

Nothing more need be said under this head. Whether we 
deserve success is now left with the profession; we will guar- 
antee to do our share as carefully and honestly as the Manual 
states it to you. To those who are yet strangers to our work, we 
take this opportunity of asking them to give us a fair trial. 

There is another point upon which we desire to make a few 
statements, which are more particularly addressed to the general 
public, however. 

The ordinary purchaser is inclined to look upon a spectacle 
mender, a watchmaker, or even the keeper of a pawnbroker 
shop, as the proper person to consult when an optical, nautical, 
or even a surveying instrument is wanted. How unfair this is! 
How can anyone sell an article of which he has absolutely no 
conception? There are numerous so-called optical stores and 
stationeries in all our large cities that will sell you almost any- 
thing in the way of scientific instruments. Even dealers in 
hardware sometimes profess to handle these goods in addition 
to their pots, pans and kettles. These men, hardware mer- 
chants, soi-clisant opticians and pawnbrokers, do not know a 



meridian from a hole in the ground, and yet they will sell you 
a mathematical instrument for meridianal observations. There 
is certainly some misunderstanding here that we should like to 
clear up. If the farmer, grader, contractor, street-builder, for- 
ester, irrigator or mountaineer wants an instrument for any 
purpose whatever, it is better that he should call on a rep- 
utable instrument-making firm at once, instead of instituting 
searches and inquiries in divers shops and hardware stores, 
where his wants cannot possibly be understood. We tell him 
this for his own benefit, for he will fare better if he takes our 
advice; he will get just what he needs, the article will be ex- 
plained to him, and he will pay less for it. 

Do you go to the shoe store for new clothing? Do you ask 
for new furniture of the man who deals in agricultural'instru- 
ments? No. But you go to the stationer for a transit, to the 
spectacle mender for a theodolite,, to the hardware store for a 
level, and to the pawnbroker for a sextant. A word to the wise 
is sufficient. 

THE A. LIETZ CO. 



INTRODUCTION 



"TTTHEN Messrs. Adolph Lietz and C. Weinmann established 
* * the present business of manufacturing scientific instru- 
ments in San Francisco some ten years ago, they realized that 
in order to compete with other makers they would have to pro- 
duce an article equal to the very best Eastern or European 
manufacture. And in no other branch of the business did this 
become more apparent than in that devoted to the construction 
of instruments for the civil engineer. With this object con- 
stantly before them, the present establishment has been gradu- 
ally built up, and has gained the confidence and the favor of 
our Pacific Coast practitioners. 

It is with great pride that the firm looks upon its success, 
for it has given to the Coast an industry that in results is not 
excelled anywhere. The motto has been: "We can build 

ANYTHING IN OUR LINE ' OUT HERE ' AS WELL AS THEY DO EAST, 

AND WHY NOT?" And with strict devotion to the pro- 
fession, and straightforwardness in commercial dealings, the 
firm has proven the maxim a sound one. 

In order to expand the scope of this establishment a stock 
company was organized in March, 1892, known as " The A. Lietz 
Company," and in the Board of Directors of this Company 
Messrs. Lietz and Weinmann associated with themselves men 
of known professional experience, both practically and theo- 
retically. Two civil engineers, Mr. C. E. Grunsky and Mr. 
Otto von Geldern, both well known on the Coast, represent the 
advisory board of the Company, for upon their suggestions, 
based upon practical experiences, the various engineering in- 
struments in use by the profession have been brought up to 
that modern standard of excellence required of an instrument 
at the present time. For this is also a policy of the new com- 
pany: to adopt at once any form of improvement which, after 
a careful consideration, has shown itself worthy of adoption. 



Vll 

Experiments incorporating new ideas are never postponed, but 
at once carried out and tested as to possible merit. 

In this wise the present forms of theodolite, transit, level, 
etc., have been evolved; and it is the purpose of this illustrated 
catalogue not only to show its readers the detailed construction 
of the instruments, but also to dwell upon individual parts, and 
to explain the methods of construction and the appliances that 
are used in creating a modern instrument of precision. 

The incorporated Company announced its new departure 
to the public in a circular letter dated March 1st, 1892, which 
we beg to republish herewith: 

We take pleasure in informing the public that the well-known firm of A. Lietz & 
Co. has been incorporated as a stock company, which will be known as 
" THE A. LIETZ COMPANY." 

The directors are Adolph Lietz, C. Weinmann, E. T. Schild, Otto von Geldern 
and C. E. Grunsky. 

These names are a guarantee that the business will be conducted on a sound basis, 
that the articles manufactured will be of the best quality, and that all work done by 
the Company will be of superior workmanship. 

The Lietz surveying instruments are too well known to require special mention. 
We shall endeavor to please our customers, and will give them the assurance that our 
constant aim shall be to produce instruments of precision with every improvement 
known to the art. 

We pride ourselves on the established fact that the firm has succeeded in develop- 
ing a HOME-MADE engineering instrument that is first-class in every particular, and 
especially designed in its details for the requirements of the Pacific Coast. We do 
not hesitate to say that this instrument will be found SUPERIOR to ninety per cent, of 
the imported articles, in every respect. 

We should deem it a particular favor if our patrons would call upon us personally, 
so that we may show them the articles manufactured, and the particular merit claimed 
in each individual case. We have closely followed the wants of the engineer, and have 
constantly endeavored to supply his needs as they became apparent from time to time. 
In this we shall continue under the advice of our directors, two of whom are practical 
field engineers well known to the profession on the Pacific Coast. 

We are also in the position to manufacture and repair scientific instruments of any 
character for astronomical, philosophical, nautical and similar purposes. 

Particular attention is called to our graduating machine, which is of the most ap- 
proved pattern, enabling us to graduate circles or arcs to any degree of minuteness; 
and to our new adjusting apparatus, where, by means of collimators, adjustments are 
possible that cannot be obtained in the field, or by any other method, with the accuracy 
and refinement required of first-class instruments. 

Repairs will have our personal supervision, and will be promptly executed. 

We shall keep on hand an assortment of field and office supplies for the Civil, 
Mining, Irrigation, Hydraulic, Military and Mechanical Engineer, and most respect- 
fully solicit the patronage of our friends and the public. 

Adding our thanks for past favors, we remain, 

Respectfully yours, THE A. LIETZ CO. 

San Francisco, Cal., March 1, 1892. 



NOTE, — The illustrations for this Manual are made from photo- 
graphs directly from the part that we desired to illustrate. These allo- 
types are evidences that the articles manufactured by the Company are 
exactly as shown upon the plates in arrangement and detail, and for 
this reason this mode of illustration was chosen as the most convincing. 
This statement is especially confined to surveying instruments, and those 
articles that are constantly kept in stock and handled from day to day. 






PART I 



DESCRIPTION OF THE ESTABLISHMENT. 



THE A. LIETZ COMPANY, 

San Francisco. 



PART I. 



Description of the Establishment. 



The location of the workshop and salesroom occupies the 
upper or third floor of the building on the northeast corner of 
Sansonie and Sacramento streets, San Francisco. 

The various departments of the business consist of the 
shop, the business office, the foundry, the graduating and ad- 
justing room, and the special nautical department. 

In the large and commodious workshop a' number of busy 
lathes, driven by steam power, are going from morning until 
evening, and at long workbenches under the light of a dozen 
windows the workmen are employed — some in the exclusive 
manufacture of new instruments for the market, others in the 
repair of such that are constantly received from all parts of the 
country. No expense has been spared to add to the shop every 
mechanical facility to increase its efficiency. 

Plate I is an illustration intending to show the interior 
view of the shop as seen from the business entrance. 

Directly in front of the work-room is the part devoted to 
the commercial interests of the establishment. A number of 
large glass showcases contain articles on sale, consisting of new 
theodolites, transits, Y-levels, dumpy levels, microscopes, tele- 
scopes, hand levels, barometers, thermometers, sectants, com- 
passes, drawing instruments of all descriptions, tape lines, 
scales, planimeters, chains, odometers, pedometers, field glasses, 
mining apparatus, mechanical contrivances, etc., etc. 

In the rear of the office is the foundry, which has recently 
been added to the establishment. It is more particularly used 



THE A. LIETZ COMPANY. 6 

and designed for aluminium castings, with which metal the 
company has lately made many experiments, and out of which 
the remarkably light transits and levels have been made, which 
shall be noticed more in detail further on. 

From the foundry a stairway leads to the roof, upon which 
the ranges for testing telescopes and other useful measuring 
and accessory apparatus are located. 

The most vital part of the establishment is the graduating 
and adjusting department, which contains the large circular 
dividing engine for graduating circles and plates to any re- 
quired degree of precision. It also contains certain valuable 
apparatus for testing the individual parts of an instrument, 
and the mural collimators for adjusting an instrument with an 
amount of exactness that cannot be obtained in the field under 
the very best circumstances. In plate II is seen the end .of 
one of the collimator levels as photographed with the interior 
view of the graduating and adjusting room. Plate VI shows 
the method employed in adjusting by means of collimators. 
It is so apparent to the eye that it will hardly require any 
further explanation. With it all the necessary adjustments are 
at once readily and precisely accomplished. 

Plate III shows the large circular dividing engine, built by 
the firm, with which all the graduations are made. The Com- 
pany has been frequently complimented on the absolute ac- 
curacy of its divisions, and on the sharpness with which the 
vernier contact may be observed under a magnifying power. 

In a paper read before the Technical Society of the Pacific 
Coast on December 5th, 1890, entitled: Some Practical Hints on 
How to Tell a Good Surveying Instrument, Mr. Lietz brought to 
the notice of the Society his experiences in graduated circles, 
wherein he refers to the true line as made by a proper cutting- 
apparatus, and as to what constitutes a good and sharply defined 
line. This professional paper has been added herewith, and 
may be found in full in Part III of this catalogue. It is repub- 
lished with the Society's permission, and the reader's attention 
is called to this short resume of the instrument maker's art. 

Plate IV shows a centering apparatus for testing the 
accuracy of graduations, and also the Company's small dividing 



4 MODERN SURVEYING INSTRUMENTS, 

apparatus for linear graduations. The former is one of the 
most useful accessories of the graduating department, where- 
with the most crucial tests of the locus of the center of the 
graduated plate are made. 

Plate V has the level tester, which is used in determining 
the degree of sensitiveness of the curvature of the glass. With 
this apparatus it is possible to obtain an accurate value of a 
division of the graduated bubble in seconds of arc. 

The same plate shows also an apparatus used for determin- 
ing the influence of the metal on the magnetic needle. 

The Nautical Department has been made a special feat- 
ure of the establishment, which possesses the facilities for 
manufacturing and repairing compasses, sextants, logs, and all 
the usual mathematical appliances of the navigator. The shop 
has adequate means for repairing mercurial and aneroid bar- 
ometers of the finest grade; an air-pump for testing an aneroid 
to any degree of atmospheric pressure, in connection with a 
standard mercurial instrument, is one of the features of this 
department. 

We are able to extend these barometrical examinations and 
repairs to those of the very finest and most delicate make, includ- 
ing the beautiful Goldschmid Aneroid, with which such remark- 
able hypsometric results have been obtained in the Alpine 
regions of Switzerland, to which reference will be made in the 
third part of this catalogue. 

Another branch of the business is that exclusively devoted 
to the making of mechanical devices, of models, or contrivances 
requiring accurate and delicate fittings. Work of this character 
has been done in the electrical line, by building apparatuses 
intended for a practical or scientific purpose. Similarly has 
this field been extended to philosophical, meteorological, astro- 
nomical, photographic, optical and other apparatus, from the 
most simple to the most delicate in character. 

The Company's importations of lenses and spirit-levels 
are of the very best European make. In the summer of 1892 Mr. 
Lietz spent several months on the European continent to obtain 
the finest articles in that line, and there is every reason to 
congratulate the firm upon the success of this investigation. 



Part I, Plate IV. 

A. UETZ CO., San Francisco, Cal. 




CENTERING APPARATUS FOR TESTING GRADUATIONS, 
In the Adjusting Room. 




LINEAR DIVIDING ENGINE, 
In Graduating Department. 



Part I, Plate V. 

A. LJETZ CO., San Francisco, Cal. 




EEVEL TESTER, 
Adjusting Department. 




APPARATUS FOR DETERMINING THE MAGNETIC INFLUENCE OF METAL, 
Adjusting Department. 



i 



THE A. LIETZ COMPANY. 

Keference will again be made to these parts in the description 
of the instruments. 

The object has been to manufacture every detail in the 
San Francisco shop; but those parts which cannot be made, 
and which are generally imported by the best makers, must be 
of the very finest quality obtainable, and for this particular 
purpose Mr. Lietz's recent European trip was undertaken. 

It would be tedious to our readers to enumerate every de- 
tail of the numerous appliances made use of in the manufactur- 
ing and repairing. Enough has been shown to convince any 
fair-minded man that this Company is enabled to manufacture 
instruments as well as any Eastern firm. And upon this fact 
we wish to lay particular stress. Why should our engineers 
send East, when they can do as well at home? By examin- 
ing our price list they will find that the prices correspond to 
those of reputable Eastern firms; but the saving lies in the 
charge of expressage, which must necessarily be greater if im- 
ported from a longer distance. 

All that is asked by this Company is a fair trial. If 
engineers visiting San Francisco will take the trouble to inspect 
the shop, we have every reason to believe that they can be con- 
vinced of what we have announced. 

We have taken pains to add a few testimonials of well-known 
men, from the large number that are on file. If anyone will 
take the trouble to peruse them he will find all our assertions 
fully endorsed. 

The Irrigation Age, published in Salt Lake City, one of the 
most popular serials in the West, has often referred to the Lietz 
Company as one worthy of the patronage of our professional 
engineers. With the permission of that journal we beg to 
quote from its March (1893) number as follows: 

The A. Lietz Company was organized in the early part of the year 1892, having 
been previously successfully engaged in the manufacture of scientific instruments. 
Particular attention has been given to surveying instruments, and it is safe to say that 
there is not a transit, theodolite or level in the market to-day that can excel the articles 
made by this Company. From the time the business was founded by Mr. Adolph 
Lietz, some ten years ago, this gentleman was fully aware of the rapid progress made 
in the manufacture of surveying instruments, and, alive to every improvement, skilled 
and trained in his profession, he has always been first and foremost in adopting every 



6 MODERN SURVEYING INSTRUMENTS, 

particular that could raise the standard of the article. The consequence has been the 
production of an instrument that seeks its equal anywhere. 

Every detail has had the most careful consideration. Of lenses and spirit-levels 
only the most perfect and accurate are used. In the matter of graduations Mr. Lietz 
has made every effort to achieve results that cannot possibly be excelled anywhere. 
The graduating machine, built in the establishment, divides circles to any required 
refinement, and with a perfection in which a wavering line, an unsteady cut, or 
an error in division have never been known. The fitting of the centres is an oper- 
ation to which a great deal of time and attention is given. It is known that one 
workman has been exclusively employed for that particular part of the work. 

Every modern accessory to an instrument is made and attached. The gradienter 
screw, for determining slopes and their degree by means of divisions on a head attached 
to the tangent-screw of the vertical movement; shifting centers; variation plates, for 
laying off the deviation of the needle; slide protectors; dust caps to leveling screws; 
verniers placed immediately under the eye of the observer; all these are advantages 
that the Lietz instrument is never without. The new tripod coupling, invented by 
Mr. Lietz, has found great favor with all engineers who have used it. It gives an in- 
strument rigidity, and insures perfect safety. The attachment of the transit or other 
instrument to its tripod is made quickly by means of three jaws that fit into corre- 
sponding grooves. Testimonials from many of our most capable engineers are con- 
vincing without further reference to the matter. 

The Company respectfully requests that all visitors to the Pacific Coast, interested 
in the articles manufactured, call at the shop on the northeast corner of Sansome and 
Sacramento streets, San Francisco. Great pains will be taken to show everybody what 
the Pacific Coast can produce in this line of delicate and beautiful instruments of 
precision. 

There is the workshop, with its lathes and mechanical facilities; the graduating 
department, for the finer work of the establishment; the adjusting room, with its col- 
limators for the most accurate adjustments possible; the nautical room, for the repair 
of compasses and sextants; and the foundry, in which the most careful castings are 
made for the use in the shop. 

This latter department was added to admit of aluminium castings, of which the 
Lietz Company has made a specialty. In order to keep up with the advancement of 
the times it was absolutely necessary to make provisions for building instruments of 
that new metal, which is beautifully adapted for this kind of work. They are now in 
the position to manufacture any instrument of this material. Up to the present time 
the Company has not placed aluminium articles in the market, but in due time a special 
announcement will be made of a new line of goods that has not seen its equal 
anywhere. 

The Pacific Coast is not behind the times in the building of scientific instruments 
of precision, and we can assure our readers that they will find every satisfaction by 
giving the A. Lietz Company a chance to do their work. 

Repairs are carefully made of all kinds of articles in this line. The firm counts 
among its customers the best engineers of California, and we can cheerfully rec- 
ommend these geutlemen to the public as worthy of patronage and consideration. 

Irrigation companies about to Jit out for field work wilt find it to their interest to con- 
sult with this Company before sending East, where nothing better can be purchased, where 
the prices for h>gh-grade goods are not any less, and the freight considerably more. 

It is quite needless to say more in behalf of the Company 
and of the extent of its work. It is the patronage of our pro- 



»2rife^&&£$&£9iitt£iii 







1 



THE A. LIETZ COMPANY. 7 

fessional engineers that we particularly desire, and their good- 
will and confidence that we wish to obtain. For that reason 
we shall devote a large portion of this catalogue to the descrip- 
tion of surveying instruments. 

It is to this subject that we wish to call your attention now; 
and if you will be pleased to follow us, you will find that we 
have not neglected any individual point in covering this broad 
field. It is our object to show you what we are doing and how 
we are doing it. 



PART II 



DESCRIPTION OF INSTRUMENTS 



MANUFACTURED BY 



THE A. LIETZ COMPANY, 

San Francisco. 

With Remarks on their proper Use, Care, Preservation 

and Adjustments. 



PART II. 



Description of the Lietz Instruments, 

Including Remarks on their Use, Handling, Care, 
Preservation and Adjustments. ■ 



THE ENGINEER'S TRANSIT OR THEODOLITE. 

In reviewing the different parts of the transit and theodo- 
lite, it will answer our purpose to include them, for the present, 
under one head, using both terms as synonymous — the word 
theodolite having been denned as an instrument of angular 
measure, possessing two graduated circles, normal to each other, 
which during manipulation are set in horizontal and vertical 
planes respectively. Bauernfeind says that it is generally 
believed that the word theodolite (theodolith) is a combina- 
tion of Oia sight, ddos road, and hep? stone. He says that 
in order to understand this derivation it must be known 
that formerly all supports upon which theodolites were placed 
were made of stone. This meaning, however, seems somewhat 
ambiguous, and other derivations have been sought. The ety- 
mology of the word is uncertain . 

In classifying there appear two distinct groups of theodo- 
lites: the simple theodolite (called by us the simplified transit), 
in which the lower clamp and tangential movement is neglected; 
and the repeating theodolite, possessing the double horizontal 
movement on spindle and plate, which is the principal feature 
of all complete field instruments made for the engineer at the 
present time. 

The various parts of the transit or theodolite may be 
grouped under the following heads, viz.: 

Beginning from the base-plate we have: 

1 — The tripod connection with the leveling, plumbing 
and centering apparatus; 



THE A. LIKTZ COMPANY. 11 

2 — The centers; 



3 — The graduated plate and verniers; 

4 — The compass and variation plate; 

5 — The standards with the vertical arc and its movements; 

6 — The gradienter; 

7 — The spirit levels; 

8 — The telescope. 

i. The Tripod Connection. 

An important feature of all Lietz instruments is that they 
are attached to the tripod by an entirely neiv device. 

It has been customary to accomplish this, heretofore, in 
two different ways. One is to attach the instrument to the 
tripod by means of a screw at the base-plate, whereby it re- 
mains complete in all its parts and is never separated above the 
leveling screws. This is the method employed by the best 
makers, but it is somewhat tedious and unsafe, as every engin- 
eer has had occasion to find out. It is often the case that the 
screw will not catch, and there is always a loss of time and 
patience in trying to enter the thread properly. Another point 
is that while turning it on, the entire weight of the instrument 
rests upon the screw thread, with a constant tendency to wear 
it away. 

The second method of fastening the transit to the tripod is 
by means of the center, making it attachable or detachable 
above the leveling screws. In most cases the foot screws may 
also be turned from the tripod head, but it is not unusual to 
have them remain as a fixed part of it. This mode of coupling 
seems to us very defective. The exposed center is liable to in- 
jury in many ways. Dust particles accumulate, and it moves 
with difficulty in consequence, if it does not cause fretting. 
But its greatest fault is the incumbent necessity of providing 
for it what is called the flat center, for turning the upper plate. 
In such an instrument the plates stand too high above the 
leveling screws, which causes unsteadiness. We believe it 
to be very difficult, if not impossible, to do accurate work with 
such an instrument, to which point we shall refer again here- 
after. 



12 



MODERN SURVEYING INSTRUMENTS, 



These substantial reasons have caused Mr. Lietz to invent 
a neiv tripod coupling, which is regarded as the most successful 
innovation by all who have had occasion to use it. 

The accompanying cut fully illustrates this simple but most 
effectual device. 

On the tripod head, instead of the ordinary screw, there 
are three jaws. The base plate of the instrument is swallow- 
tail-shaped on the inside (as shown at F), and is provided with 
the spring case C. The coupling of the two is done by letting 
one of the grooves on the base plate meet any one of the jaws on 
the tripod head, when one-third of a revolution to the right 
will make the connection; at the same instant the spring C will 
fall into a hole on the tripod head, which thus prevents any 
possible disconnection ; the latter is effected by lifting the spring 
C and turning to the left. If the tripod head should have been 
worn or bent by accident, the movable jaw D, which is worked 
by the side-screAV E (with a large adjusting pin), will again give 
the coupling friction enough to hold the instrument perfectly 
firm on the tripod. 

Figure I. 




The chief merit of our arrangement is that it enables one 
to attach or detach the instrument to or from its tripod more 



THE A. LIETZ COMPANY. 13 

rapidly, firmly and safely than by any other device so far known, 
and that, too, without dividing the instrument proper into two 
parts, which is always injurious to its accuracy and stability, as 
we have just pointed out. To this we may add that it is more 
durable, easier to keep clean and cannot get out of repair. 

The movable jaw, once set for the instrument, need not 
again be interfered with. It is absolutely needless to adjust 
the friction every time the instrument is placed on the tripod. 

We feel quite confident in saying that every engineer who 
has once used this new coupling will readily detect its great 
merits, and will never be without it. All the large-sized trans- 
its and levels of the Lietz make fit the same tripod head, and 
are instantly adjusted. 

a. Leveling Screws. 

As these are used more than any other part of the instru- 
ment, it is evident that they should be very durable. Those of 
the Lietz make possess a very deep thread, rounded a little on 
the edge, which insures a very smooth motion and greater dur- 
ability than sharp-edged threads. The screws are made of 
composition metal. 

The lower construction of the transit is made with the view 
of affording the greatest steadiness under all conditions. For 
that reason the leveling screws are not run through a thin 
metal disc, with a common nut attached for their operation, 
but an extra strong, star-shaped casting, made in one piece, is 
provided, through which the screws are passed and in which 
they operate. This " star piece " A (see the preceding engrav- 
ing, Figure I), is slotted, so that any lost motion of the leveling 
screw may be taken up by the clamp screw B. This feature is 
of great importance in leveling instruments or transits used for 
leveling. 

The whole construction of this part is intended to insure 
the absolute steadiness of the instrument, and to give it rigid- 
ity even in a strong wind. Any other construction, with a 
light disc parallel to the base plate, cannot afford that stability 
which a first-class transit or level should possess; and, since 
this is one of the prerequisites of an instrument of precision, 



14 MODERN SURVEYING INSTRUMENTS, 

we have laid particular stress upon our leveling arrangement, 
which is of the most approved modern design. 

The screws are protected by dust caps, if desired, which is 
a necessary addition, adapted to the climate of the dry summer 
of certain of our Coast localities. 

For instruments of the greatest precision, as those used in 
triangulation or geodetic work, it may be an advantage to ar- 
range the base with three leveling screws instead of four. 
These changes will always be made upon application. While 
the ordinary complete transit is more compact and of greater 
utility with four screws, in a specially designed instrument for 
the finest work it will always be well to consider the advantages 
of the three-screw system, universally adopted in European 
instruments. 

b. Shifting Center for Facilitating Plumbing and Centering. 

All our complete instruments are furnished with shifting 
plates for the purpose of setting them precisely over a point. 
after having approximately done so by the tripod legs. This 
arrangement is of the greatest utility to the field man, and we 
are convinced that those who have adopted it will never again 
dispense with it. 

While it does not make the instrument less rigid or port- 
able, it is so easily manipulated, and becomes a great labor- 
saving factor. In order to center the instrument accurately. 
two of the leveling screws require a slight loosening, when the 
transit may be shifted upon the tripod until the center of the 
plumb-bob is directly over the point to be occupied. The 
screws are then turned down and the instrument leveled up in 
the usual manner, when it will stand as firm upon its base as 
required. We have placed a thin metal plate under the level- 
ing screws, intended to prevent the accumulation of dust between 
the two shifting plates. 

2. The Centers. 

In manufacturing this all-important feature, the very back- 
bone of the instrument, too much care and attention cannot be 
bestowed. 



THE A. LIETZ COMPANY. 15 

It is essential that both of these metal axes should have the 
same absolute center as the graduated plate and the horizontal 
telescope axis, whichever way the instrument may be turned. 
This is accomplished by the A. Lietz Company by making this 
detail a specialty. The carefully chosen material for the ver- 
tical axes, the exact method of turning and fitting them, and 
the precision reached in the manner of centering them, to- 
gether with the subsequent scrutinizing test to determine the 
slightest eccentricity, have accomplished results as perfect as 
mechanical means and human ingenuity can achieve. 

Eccentricity has been a source of annoyance and error to 
the engineer, to determine which a number of practical meth- 
ods have been invented and put to use. One of the most in- 
genious has been inserted in this catalogue, which will be found 
in full elsewhere. 

But with our modern transit, if used with ordinary care, 
this source of error has been eliminated, or at least reduced to 
the lowest possible minimum. 

The length of our centers is from 2| to 4 inches, according 
to size and style of instrument. To our best belief, this is 
more than the instruments of any of the many different mak- 
ers possess, having constantly handled a great many of them in 
repairing. Yet, by examining our illustrations, it will be no- 
ticed that with us the limb and vernier plates are nearer to the 
tripod head than in those of other make, owing to the judicious 
placing of the centers, which reach down into the base, thus 
insuring the utmost stability. By comparing our cuts with 
those in other catalogues, the reader will obtain a pretty fair 
idea of what we mean to impress upon him — such a comparison 
being better than any argument by either ourselves or others, 
based upon mere assertion. 

Examine carefully our construction of the centers, and 
you will be soon convinced that our claim for rigidity and sta- 
bility is fully warranted. 

3. The Graduated Plate. 

We have now come to the most essential part — the very 
soul of the instrument. It is needless to dwell upon the neces- 



16 MODERN SURVEYING INSTRUMENTS, 

sity of an accurate graduation; it is self-evident, and it becomes 
the instrument-maker's pride to make it so. 

We guarantee our work in this particular as perfectly reli- 
able, the graduation lines straight, thoroughly black and of 
uniform width. 

The plate is accurately centered and free from eccentricity, 
as already explained. 

The horizontal circle is graduated from to 360 degrees, 
with two sets of figures running in opposite directions (unless 
ordered differently). They are large and distinct, and, to 
avoid errors in reading, the figures of these two sets, and those 
on their corresponding verniers, are inclined on opposing slants, 
thus indicating the direction in which the vernier should be 
read. 

We recommend graduations on a solid silver ring, as that 
metal offers many advantages for the purpose — in fact, its great 
permanency and smoothness renders it the only satisfactory 
surface for fine graduations. However, they are made as the 
customer desires; but since the additional outlay for silver 
graduation is only 110, we seldom have any difficulty in im- 
pressing the purchaser with its advantages. 

It is customary with us to graduate circles so that they may 
be read to thirty seconds or twenty seconds of arc. We make any 
degree of refinement called for, but our manufactured goods are 
always on hand in the two vernier divisions named. 

a. The Vernier. 

This consists of a small sliding scale, movable upon a 
larger one, so graduated that n parts thereof shall include either 
n-\-l, or n — 1 parts of the larger scale. The scale may be 
applied to either straight lines or arcs, and aids to determine 
the smaller divisions of measure between the lines on the 
larger scale. 

A tedious method for measuring small values of arc by 
means of concentric circles was given in the early part of the 
sixteenth century by a Portuguese, Pero Nunez (Nonius), and 
after him the name of nonius is still applied in Germany and 
other countries to what we exclusively call a vernier here. 



THE A. LIETZ COMPANY. 17 

This term was justly given it in honor of the Dutch captain, 
Peter Werner, who gave to the scale the sliding shape in which 
we now apply and use it practically. Signing himself " Pierre 
Vernier " in a discussion of the "Nonius," written by the in- 
ventor in the French language and published in Brussels in 
1631, gave rise to the term we now almost universally employ. 
The graduations on a vernier are usually so made that n 
divisions thereof shall equal n — 1 divisions on the chcle. 

It becomes a simple problem to determine the value of n 
from the following equation: 

Let I = length of one division on circle, 

h— length of a vernier division, it is evident that 
I (n-1) = li n , or 
I 

The value of any quantity in the equation may then be 
readily expressed in terms of the other; I — U, or the smallest 

readable division, being equal to — . 

n 

It is customary to graduate the circles of the Lietz transits 
in 20-minute divisions, reading to either 20 or 30 seconds on 

the vernier. The value of n in these cases is , or 60 in 

20 ' 

20 X 60 
the former, and — — , or 40 in the latter; or, in other words, 

59 and 39 divisions on the circle will correspond to 60 and 40 
on the vernier respectively. Instruments reading to one min- 
ute of arc are divided to 30 minutes on the plate; in that case 

29 circle spaces are equal to 30 vernier spaces. 

Every good instrument should have two verniers; they 
should be covered with glass to protect them from exposure, 
and for ease in reading they should be provided with ground 
glass shades. 

Our verniers are in such position that the observer need 
not step aside in order to read them, for we place them about 

30 degrees from the line of collimation. The method of thus 
placing them has been pronounced objectionable, because the 
size of the plate level, which is at right-angles to the line of 
collimation, and the more important of the two, has to be re- 



18 MODERN SURVEYING INSTRUMENTS, 

duced. By examining our instruments, however, anyone will 
see that we have attained the object without reducing its length, 
without placing it over the vernier, and without allowing it to 
extend beyond the circumference of the plate — -all of which 
would be very objectionable features, indeed. 

The space between the circle and the vernier must appear, 
through a magnifying glass, like a fine black line. No accurate 
reading can be taken if the space appears wider than a mere 
line of uniform thickness under the revolution of the plate. 

b. Clamp and Tangent Sevens. 

The lower clamp screw of our transit is of the best devised 
shape and arrangement. It is strong and rigid, and answers 
the slightest touch. 

The upper clamp does not come in contact with the limb, 
but grasps the sleeve of the outside center. This is far prefer- 
able to the old method of pressing together the two plates by 
means of a screw placed at some point on the circumference. 

The tangent screws are single only, and operate in metal 
cases against opposing springs. Great care has been bestowed 
in eliminating all lost motion of these screws. We consider 
double tangent screws, working against a tongue, as entirely 
obsolete. Any instrument sold to-day with double opposing 
tangent screws may be set down as antiquated and behind the 
times. It is absolutely necessary that everything tending to 
create lost motion must be carefully avoided. While adjusting 
the line of collimation, this source of error becomes very 
annoying, for, in revolving the telescope, the plate is liable to 
turn slightly and the operator is never sure whether the cross- 
hairs are in adjustment or not. 

The arrangement of our tangent screws combine simplicity 
with absolute reliability. Being single, they require but one 
hand in manipulation, and their judicious location and spring 
case arrangement make them active and operative at any 
instant. 

4. The Compass. 

Our needle differs somewhat in shape from others, being a 
little smaller in the center than towards the ends, for the reason 



THE A. LIETZ COMPANY. 19 

that the magnetic influence is manifested at the ends only, so 
that all the central metal may be called dead weight. Compared 
with those of other makers, the Lietz needle is, therefore, a 
little lighter, which conditions the increased durability of the 
point upon which it poises. 

Hard steel has the capacity of retaining magnetism longer 
and better than when tempered, and for that reason we have 
adopted the plan of leaving one-half inch on both ends per- 
fectly hard. 

The closest attention is given to the center cap — which 
contains an agate setting — and to the pin upon which the needle 
rests, for the accuracy or sensitiveness depends principally upon 
these two details. These needles possess that degree of sensi- 
tiveness required in a high-grade instrument. A sluggish 
needle — one that will hang like a dead load — is not fit for the 
observation of a reliable azimuth. 

The center pin must occupy the true center of the gradu- 
ated circle, and must stand normal to its plane. We utilize 
precise instruments with high magnifying power to obtain the 
absolute true position of the pin, in order to avoid all errors 
due to eccentricity. 

The lifting arrangement is applied with the view of raising 
and lowering the needle gently and gradually, as any sudden 
drop to the pin, or any quick action of arresting its motion, is 
sure to cause a rapid wearing of the point and the cap. 

The Compass is divided into 30-minute divisions, and num- 
bered from to 90 degrees in each quadrant from the north 
and south points. This is done to conform with the usual 
practice of surveyors in this country to record bearings in the 
four quadrants. But any desired method of numbering the 
compass, either from to 180 degrees, or from to 360 degrees, 
may be had upon application. 

In order to record at once the true bearings in the field, 
instead of the magnetic, the complete instrument is provided 
with a variation plate, i.e., an arrangement for laying off the 
local deviation of the needle by a movement of the graduated 
compass ring, so that the indicated course of a line shall show 
at once its relation to the true meridian. It is so made that 



20 MODERN SURVEYING INSTRUMENTS, 

the variation may be laid off as closely as required with the aid 
of the instrument's vernier. 

This is done in the following manner: 

Having set the plate vernier to zero, adjust the instrument 
and, with the aid of a good reading glass, place it in such a 
direction that the north end of the needle shall point to the 
zero of the compass ring, which latter must coincide with the 
little pointer provided for that purpose. Having carefully set 
the instrument thusly by means of the lower clamp and its 
tangent screw 7 , which can certainly be done to the nearest 
minute of arc, we release the clamp of the plate and proceed to 
lay off the amount of the local deviation of the needle in de- 
grees and minutes by means of the plate-vernier — to the left 
if the variation be east. The instrument is now again in a 
fixed position, the telescope pointing to the true north, or as 
much to the left of the needle as the magnetic variation is east. 
We now detach the little screw on the side of the compass ring, 
and proceed to turn the ring until its zero shall coincide exactly 
with the north end of the needle, when every subsequent read- 
ing of the compass, in any position, will indicate the bearing 
of the vertical telescope axis from the true meridian. 

This simple little device is fully up to the standard of ac- 
curacy required, for with care in setting the needle we can 
always obtain results correct within the nearest minute. We 
find that by this method the additional vernier, usually placed 
inside of the compass ring, becomes superfluous, as the plate 
and vernier of the transit are perfectly capable of taking care 
of the duties of this unnecessary accessory. 

The variation plate has proven a great labor-saving device, 
as the observed courses require no reduction to the true merid- 
ian subsequently. It is now almost universally called for; and 
for those practicioners with whom land surveying is a specialty 
we should, by all means, recommend it as an indispensible 
feature. No complete instrument is without it. 

5. The Standards and Vertical Arc. 

The standards are so constructed as to give the maximum 
support to the telescope, commensurate with the size of the 
plate. They are light, but rigid and strong. 



THE A. LIETZ COMPANY. 21 

To avoid unequal expansion of the metal in the standards 
by exposure in the hot sun, which has a tendency to elevate 
one end of the telescope axis and to depress the other, vitiating 
the adjustment, they are now what is called cloth-finished. 
This finish, being a non-conductor of heat, reduces to a mini- 
mum this source of possible error, which, in very sensitive 
instruments, is of sufficient moment to be guarded against. 
Other parts of our instruments are also finished in the same 
manner, particularly level telescopes, which we shall have 
reason to mention again hereafter. 

The bearings for the telescope axis are made with extra 
care and attention. 

The axes of the Lietz transit telescopes are cut to conical 
bearings, which is a feature altogether preferable to the cor- 
rugated shape frequently found in surveying instruments. 
The advantage of the former is very evident, in that there is 
less friction than by any other contact; and, in addition to 
that, it affords a much finer fitting by reason of its conical 
shape. But it is very essential that the hardest metal should be 
used for this purpose, as a material of insufficient hardness 
would soon wear, and the axes would become elliptical. 

One of the standards is supplied with an adjusting screw, 
to regulate any inaccuracy in the motion of the telescope in 
the true vertical plane, when the centers of the instrument 
stand vertically. 

One standard carries the arc for observing vertical angles, 
which may be either a full or a half-circle, as the customer de- 
sires. It is usually made to read to minutes, but may be grad- 
uated finer if so ordered. A clamp and tangent screw are 
provided on the right-hand standard, which are made like those 
already described for the horizontal movement. Every part of 
the vertical measuring apparatus is strongly and accurately 
made and fitted, to insure the best results in its practical appli- 
cation . 

6. The Gradienter. 

The head of the tangent screw of the vertical arc move- 
ment is made somewhat larger, properly silvered and graduated 
into a number of equal parts on its circumference, the thread 



22 MODERN SURVEYING INSTRUMENTS, 

of the screw being cut with great precision, so that its revolu- 
tion may be accurately recorded by the divisions of the 
micrometer head. 

One complete revolution of the screw corresponds to T 5 -g- of 
a foot of difference in level in 100 feet. Since the head is di- 
vided into fifty parts, it follows that one division equals a dif- 
ference of i4o of a foot in 100 feet. 

With this attachment grades may be established very 
quickly. It is only necessary to set the screw head to zero, 
level and clamp the telescope, and turn the screw up or down 
as many spaces as there are hundredths of a foot of rise or fall 
in one hundred feet of the grade to be laid out. With the 
small scale over the screw thrown back, the gradienter is used 
as an ordinary tangent screw. It is one of the most useful ac- 
cessories, is easily applied, and adds nothing to the weight of 
the instrument. 

This attachment is also useful in the determination of hor- 
izontal distances, it being obvious that the difference in rod 
reading between two complete revolutions of the screw will in- 
dicate at once the distance of the rod from the observer. Where 
the ground is level, or nearly so, the simple difference in rod 
reading will suffice; but when this is not the case, the necessary 
corrections will have to be applied to obtain the true horizontal 
distance. 

7. The Spirit Levels. 

We have already noted that for our purposes we import the 
very best article obtainable in Europe. 

An instrument of precision, capable of measuring delicate 
differences, requires delicate and sensitive levels. This is so 
obvious that we ought not to call attention to it here, were it 
not for the fact that we are frequently approached by surveyors 
who wish to impress upon us the idea that this or that make of 
instrument met with their approval because its bubbles would 
stay in place when once adjusted. For this reason we want to 
repeat that it is no claim for superiority of a spirit level because 
it works sluggishly. An engineer in the field must know when 
his instrument is absolutely level, and its bubbles should indi- 
cate to him at once when this is not the case. If they do not 



THE A. LIETZ COMPANY. 23 

do so, then the instrument does not come up to the required 
standard of a precise tool. It would hardly do to place a car- 
penter's level on a transit, yet we have no doubt that its excel- 
lent qualities of remaining stationary would find admirers. 

Remember, also, that sluggish levels are cheaper, and that 
it is not to the instrument-maker's financial benefit to put in a 
delicate and, therefore, much more costly article. 

There is, of course, a limit to the degree of sensitiveness, 
and that we never exceed, adapting it in all cases to the work 
demanded of the particular instrument in hand. 

Our levels are ground to the proper curvature, and each is 
carefully tested upon our level tester before it is attached any- 
where. 

8. The Telescope. 

We have now reached another most essential feature of the 
instrument — that which may be compared to the head of the 
body, containing the delicate organ of sight — the lens. 

a. The Lenses. 

We have already called attention to the fact that our optical 
accessories are imported from Europe, and that we take great 
pains to obtain the best article for the purpose. 

Without going into the detail of optical mathematics and 
formulae, that can be readily found in any text-book on physics, 
we all know that it has been the constant aim to produce lenses 
as free from spherical and chromatic aberration as it is possible 
to make them. The lenses of the Lietz telescopes are of the 
now celebrated Jena glass — an achievement in theoretical and 
practical science that ten years ago was unknown, and of which 
it would be interesting to make some explanation here. 

The Jena Glass Works. 

The far-famed glass melting works for optical and scientific 
purposes of Schott and Associates, in Jena, was founded in 1884 
by men who were of eminent scientific attainments, and who 
based the magnificent industry upon long continued research 
in this particular field. Our information comes from a short 
description furnished by the leading men of the enterprise, 



24 MODERN SURVEYING INSTRUMENTS, 

which was published some time ago in connection with a list of 
the glass varieties manufactured. 

The industry originated from a series of scientific investi- 
gations made for the purpose of determining, from their chem- 
ical combinations, the resulting optical properties of fusible 
compositions having an amorphous congelation. These exper- 
iments were undertaken by Professor Abbe and Dr. Schott, to 
obtain information regarding the chemical and physical prin- 
ciples underlying the manufacture of optical glass. This work 
began in January, 1881, and was prosecuted in accordance with 
a pre-arranged plan in such wise: that Dr. Schott made the 
necessary melting tests at his home in Witten, Avhile the optical 
investigations of the samples obtained were carried on in Jena 
by Professor Abbe, or his assistant, Dr. Riedel, by means of 
spectroscopic analysis. 

The melting tests were made at that time on a very small 
scale (not over 300 to 900 grains in bulk), and were solely di- 
rected to the one object of studying carefully the influences of 
all chemical elements that may possibly obtain in auy form in 
amorphous fusible compositions, upon the power of refraction 
and dispersion in their manifold combinations. 

By carefully continuing the investigations in this manner 
to the end of the year 1881, a number of facts and data had 
been collected regarding the specific optical effect of certain 
masses, which gave promises of new glass combinations that, 
for certain purposes, would possess more advantageous charac- 
teristics than those offered by the ordinary crown and flint. 

In order to utilize these results in practical optics as much 
as possible, it was decided to continue the work on a new plan, 
and that was: to combine systematically glass fusions on the 
optic-chemical principles established by the preceding experi- 
ments that should possess, as far as possible, all the desirable 
optical properties, together with other physical qualities fitting 
them specially for practical use, such as hardness, unchange- 
ableness, freedom for color, etc. 

With this end in view, Dr. Schott removed his residence 
to Jena in the spring of 1882, where a special laboratory, with 
every facility for melting, was fitted up in a building rented for 
the purpose. 



THE A. LIETZ COMPANY. 25 

With the aid of gas furnaces and modern blowing appara- 
tus, it became possible to make melting tests on an amply large 
scale, up to quantities of about 25 pounds. 

With the assistance of another chemist for the analytical 
investigations, which had to be carried on simultaneously with 
the synthetical work, and one workman, the tests were contin- 
ued in this laboratory until the end of the year 1883, whereby 
two special lines of investigation were closely followed, which 
practical optics had laid out as the principal directions of re- 
search. 

The first problem considered the making of crown and flint 
glass couples, possessing as near as possible a proportional dis- 
persion in the various sections of the spectrum, for the purpose 
of obtaining a higher degree of achromatism than had hereto- 
fore been possible by employing the usual optical glass; that is, 
it was sought to obviate, or to reduce the very considerable sec- 
ondary aberration, which the silicate glasses still permit in all 
their achromatic combinations, and which is due to the dispro- 
portionate dispersive powers in crown and flint. 

The second problem — considered of no less importance, 
although the subject involved had, generally speaking, not been 
deemed a necessary feature in optics up to that time — consisted 
in obtaining a greater variety of gradations or modifications of 
the two principal constants in optical glasses, viz.: the expo- 
nent of refraction and the mean dispersion. 

The silicate glasses in use at that time, true to the simplicity 
and uniformity of their chemical constituents, show images of 
a simple series in which, ascending from the lightest crown to 
the heaviest flint, the dispersion increases in the same measure 
as the exponent of refraction increases, up to very small and 
practically immaterial deviations. 

But the theoretical consideration of dioptric questions 
establishes without doubt, that it would simplify greatly this 
problem, in which numerous conditions are to be fulfilled at 
the same time, if the optician had his choice of such glasses, in 
which the dispersion with the same index of refraction, or the 
index of refraction with a constant dispersion, could be made 
to undergo a very considerable gradation. In this direction it 



26 MODERN SURVEYING INSTRUMENTS. 

must be looked upon as a progressive step, that the systematic 
use of a greater number of chemical elements in glass fusions 
makes it possible to create the varying grades referred to — that 
is, it enables one to extend the variety of glasses at disposal, in 
some places at least, in two dimensions, which heretofore had 
been essentially linear in character; but the realization of this 
advance in practice may only be expected gradually, because of 
the necessity of supplying further theoretical and mathematical 
bases for these productions. 

The experiments led to the most satisfactory results, which, 
for the purpose of our catalogue, it would be unimportant to 
elaborate in further detail; suffice it to say that the faithful 
endeavors of these men were universally appreciated, and that 
their conclusions gained the fullest confidence of those who 
were best able to judge of the value of their labors. 

The results were reached in the autumn of 1883, and the 
entire research would have been completed then, had it not 
been for the instigation on the part of several prominent 
scientists, that the investigators take hold of the practical ap- 
plication of their theoretical achievements themselves, and to 
begin the industrial production of this article immediately in 
connection with the preceding laboratory research. 

This finally led to the erection of glass melting works at 
Jena, with all the facilities for successful practical operation, 
established with the cooperation of Doctors Carl and Rod. Zeiss, 
who had previously given valuable assistance in the preliminary 
investigations. In the autumn of 1884 the factory was in con- 
dition to prepare for the production of optic glass on a large 
scale — both of the kind previously in use, as well as that of the 
newly created combinations. 

To carry out the necessary and very expensive experiments 
on a factory scale, it was fortunate that means were furnished 
by a number of liberal appropriations granted from the Prussian 
State Treasury, which received the hearty endorsement of all 
scientific circles. 

After surmounting great and numerous difficulties, natur- 
ally retarding the progress in a new technical field, in which the 
enterprise is thrown entirely upon its own resources, without 



THE A. LIETZ COMPANY. 27 

any assistance from previous experience, the Jena factory has 
now become a successful industry that has made its way to re- 
main as a valuable permanent feature. Its capabilities have 
been sufficiently tested during the last eight years, in the inter- 
course with most of the optical works in Europe, so that it is 
now fully able to compete with them on a commercial basis. 

These remarks on the Jena glass factory will convince the 
reader that the article deserves that general preference which 
is universally given it — its evolution is one based upon a true 
scientific foundation — for, in this case, the practical appli- 
cation depended entirely upon a previous theoretical research, 
and theory and practice must work hand in hand to achieve 
lasting results. A new era in optics began when the Jena 
glass became a merchantable article. And this new optical ad- 
vance was not without effect upon those fields of science in 
which optical apparatus is used, for the achievements in one 
particular line alone — in microscopy — received a fresh impulse 
from that time, which was again felt in other departments, as 
in physiology, biology, bacteriology, hygiene — those most im- 
portant to the welfare of man. 

This short diversion leads us again to the subject of the 
telescope for engineering purposes, with which we are more 
particularly concerned. 

6. The Object Glass. 

Arrangements have been made by which our lenses are 
specially ground for us in Europe, and not one is accepted that 
will not stand the most critical test. We receive objectives 
and eye-pieces in sets at stated periods, so that we are always 
in position to supply our demand. Neither time, trouble nor 
expense has been spared to produce a telescope up to the stand- 
ard of the most approved pattern, that shall possess all the 
refinement required of an instrument designed for scientific 
work. 

The objective is formed by a combination of two lenses, a 
crown and a flint glass, one of which is bi-convex, the other 
plano-concave. The inner faces have the same curvature. 
As the concave lens has the longer focal length, this combi- 
nation maintains the characteristics of one convex lens. The 



28 MODERN SURVEYING INSTRUMENTS. 

focal lengths are so proportioned that the dispersion caused by 
the crown-glass lens is corrected by the flint — the well-known 
principle of counteracting the dispersion of light of one lens by 
interposing another of a different glass is made use of. 

Our objectives possess these achromatic lenses, made of the 
Jena glass, with special care, by the most skilful opticians. The 
focal lengths of these objectives vary from 171 inches, in the 
case of the large Y-levei, to 10 inches, in the large transit, 
and to lh inches in the smaller instrument. 

In mounting the two lenses in the cell, great care is taken 
that their axes are made to coincide. Should this important 
point be neglected, an indistinctness of image would be likely 
to result. 

c. The Eye-Piece. 

The simplest form is the so-called Ramsden eye-piece, in 
which two plano-convex lenses are mounted so as to turn the 
convex surfaces towards each other. The distance between 
them is such that the chromatic aberration of one lens is cor- 
rected by the other — which, however, is not fully accomplished. 

Another form of eye-piece was invented by the optician 
Karl Kellner, of Wetzlar, and fully described in a paper pub- 
lished in 1849. It was called the orthoscopic ocular (from <>/>#"? 
straight, and <jvm-zuj observe), by reason of its principal ad- 
vantageous feature of furnishing of every object a straight, 
perspectively correct, and, in every extent, sharp and well de- 
fined image. The Kellner eye-piece also consists of two lensesT 
a biconvex collective, of which the flatter curvature is turned 
towards the objective, and an achromatic eye-glass, whose con- 
struction is similar to the Fraunhofer achromatic lens. 
According to the inventor's description, the three lenses used 
in this eye-piece possess only four reflecting surfaces, and the 
two lenses composing the eye-glass must therefore come in ab- 
solute contact with each other. There may be two forms of the 
eye-lens: a plano-convex, with the curved face towards the 
collective; and the doubly-convex. 

An ocular of this order, wherein both the collective and 
the eye-lens are compound, is the Steinheil eye-piece, which is 
doubly achromatic, but which gives a very flat field. 



THE A. LIETZ COMPANY. 29 

These forms of positive eye-pieces, wherein the focus of the 
objective lies in front of the combination, together with several 
of the negative form (the Huyghens and the Airy), wherein the 
objective's focus lies between the two lenses, give an inverted 
image, which is considered by many as an undesirable feature 
in surveying instruments. Nevertheless, they possess many 
valuable points in their favor, and for that reason they are uni- 
versally adopted in Europe. In the first place this form admits 
of a greater amount of light than the erecting eye-piece. It 
also allows a longer focal length to the object glass, which is 
very important in correcting spherical aberration, besides in- 
creasing the magnifying power, which is a value dependent 
upon the ratio of the focal lengths of the object glass and eye- 
piece. 

We have always considered this inverting form the more 
advantageous oLthe two; and we are convinced that if our en- 
gineers would accustom themselves to its use, it would finally 
be preferred. There is absolutely no difficulty in the inverted 
position of objects, and it is remarkable with how little effort 
the mind adjusts itself to it, so that the work may be done just 
as expeditiously as though the observer saw the objects erect. 

But, as the erecting eye-piece is in general demand, we do 
not intend to introduce the inverting one; all that we wish to 
point out is that the latter possesses many advantages not gen- 
erally sufficiently considered, and that seeing objects upside 
down is not an obstacle at all, for upside down and right side 
up are only relative impressions, which impose no task upon 
the brain. If the professors of civil engineering in our colleges 
would draw more attention to these facts, the results would soon 
be quite gratifying. 

The erecting or terrestrial eye-pieces require four lenses, 
placed so as to correct the chromatic aberration. In this form 
the inverted image of the object glass is again inverted, and an 
erect one is created between the third and fourth lens, which is 
viewed and magnified by the fourth. This is the form used 
for our transits and levels, and we can again insure our patrons 
that in this line nothing better is produced. The optical pow- 
ers of the telescope are in perfect keeping with the accuracy of 



30 MODERN SURVEYING INSTRUMENTS. 

the centers, graduation and spirit levels, insuring a complete 
reliability and harmony in every part of the instrument for the 
most refined surveying work. 

The eye-piece (always erect unless specially ordered) is so 
arranged as to permit its easy removal, if necessary, by simply 
unscrewing it. In replacing, it should always be well tightened 
up. It is movable in and out by a revolving motion, turning 
the cap about one-sixth of a revolution backward or forward — 
a manner which affords a finer and more precise focusing of the 
cross- wires than by means of a rack and pinion. 

Having reviewed generally the optical details of the tele- 
scope, we shall describe in a few words the mechanical construc- 
tion of its other parts. 

d. Other Parts of Telescope. 

The slide, to which the object is attached, fits directly in the 
outside or body of the tube. Particular attention is paid to 
this part to prevent even the slightest shake, and still procure 
an equal and sure motion, which is absolutely necessary, as no 
true adjustment of the line of collimation is possible otherwise. 
The motion is given by a rack and pinion. 

The sliding tube is protected from dust and dirt by an ex- 
terior metal cylinder, called the slide protector . 

A sun shade is provided for the objective, which should al- 
ways be attached, as the telescope, when focused to mean dis- 
tance, is balanced with it; and a cap is provided for the protec- 
tion of the objective when not in use. 

The cross-wire frame is suspended in the tube by four 
capstanheaded-screws, by which it is adjusted, the- frame being 
so constructed that the cross-wires cannot be torn, in case the 
adjusting screws are tightened too much. 

The spider web used for our instruments is properly treated 
to avoid all twist, and to prevent its lengthening and becoming 
crooked in damp weather; it cannot become loose, as it is well 
secured. 

For mining and tunnel transits we can provide proper 
means for illuminating the cross-wires — an arrangement that 
is readily supplied upon application. 



THE A. LIETZ COMPANY. 31 

Quite a number of glass diaphragms have been cut by 
us for the United States Coast and Geodetic Survey. In- 
stead of the spider webs, a small disc of very thin glass is 
fastened to the diaphragm, on which fine lines have been drawn 
with a diamond. It is readily seen that these cannot get out 
of shape, and for stadia measurements we think them of great 
advantage. The only drawback is that small particles of dust 
may settle on the glass disc, and, as they are in the focus of the 
eye-piece, they will be constantly visible to the observer. 

We make no extra charge for putting these diaphragms 
into our new instruments, if ordered in time. 

Stadia hairs are placed in all our transits (and levels), unless 
ordered without. We have superior facilities for setting them 
with great precision to any desired ratio between distance and 
rod reading. It is customary to place them so that they shall 
read 1 foot on the rod for a distance of 100 feet, and to this 
measure we always have them in our stock on hand. 

The stadia hairs may be fixed or adjustable. We advise the 
fixed, as they are less liable to change their distance. In an 
adjustable set the observer is never certain that the position of 
the wires has remained unchanged. We have constructed a 
delicate optical and mechanical apparatus for fixing stadia hairs 
accurately to any proportion; and by means of our powerful 
telescope, which has superior optical qualities, we can safely say 
that, with proper care and a little experience in that method of 
measuring, very satisfactory results may be obtained. The 
facilities for measuring across inaccessible places, and the speed 
with which it enables one to get distances, has brought this 
method into deserved prominence with our engineers. For 
topographical surveys it is indispensable. 

For the benefit of our patrons we have added a short 
treatise on stadia measurements, together with a table for cor- 
recting the observed reading to the horizontal distance and dif- 
ference in level, which see in Part III. 

When purchasing a new instrument, it is advisable to get 
one that has fixed stadia wires, which increases the cost only 
$3, while we charge $10 to put them into a transit sent to us 
subsequently. 



32 MODERN SURVEYING INSTRUMENTS. 

Ill sighting with the telescope it is of considerable advantage 
to have it reversible, and our transits are made so as to allow this 
free revolution in a vertical plane. The telescope balances ac- 
curately when in focus to mean distance, the friction in the 
bearings being shaded to such a degree of nicety that it shall 
neither work too hard nor too loose — a feature which ought to 
have very close attention. 

e. General Remarks about Telescopes. 

When selecting or examining an instrument, the engineer 
should be particularly careful to test the qualities of the tele- 
scope. 

It should have sufficient magnifying power to correspond 
with the finer qualities of the graduation, axis, centers, spirit 
levels, etc., of the instrument. There can be no doubt that 
the excellencies of each detail must compare with that of any 
other. 

Now, by using a low-power telescope, the defects of an 
inferior instrument may be hidden, or left undiscoverable , and for 
this reason they will always be found in articles of lower grade. 
Had such an instrument lenses of sufficient magnifying power, 
the defects would become apparent to the engineer at once. We 
lay the greatest importance upon these facts, and for this reason 
call particular attention to them. Scrutinize the optical abilities 
of the telescope, and you will obtain the character of the whole in- 
strument . 

For obvious reasons, some makers — but more especially 
dealers — give the magnifying power of the telescopes of their 
instruments much higher than it really is. An engineer should, 
therefore, be careful to convince himself of the real magnifying 
power before making a purchase. He will find it much to his 
interest to do so. 

We have found that the power of first-class instruments 
should be about twice as many diameters as the length of tele- 
scope expressed in inches. In inverting telescopes it may be 
materially increased, which shows again that they are of con- 
siderable importance in very high grade instruments. 

In another place we have added a practical method for find- 
ing the magnifying power of a telescope, to which we would 



THE A. LIETZ COMPANY. 33 

advise our engineers to give some attention, and to make use 
of when about to choose an instrument. 

We have already pointed out the importance of perfectly 
centering the lenses, especially the objective. If this is not 
properly attended to, the adjustment can never be perfected for 
long and short distances. 

We have heard many complaints from engineers about the 
change in adjustment, and after careful examination we have 
found that the adjustments remained intact, but that the fault 
lay in the objective, which had not been correctly centered. 
We take great pains to center our object glasses perfectly, and to 
insert the lenses in such a manner that if taken out they may 
be replaced in the old position, which is secured by a notch and 
a pin. It is not advisable for engineers, however, to take these 
lenses from the cell, as their cleaning may be effected without 
removing them. 

Reverting again to the magnifying power of telescopes, it 
may be asserted that an increase thereof reduces the field. This 
is no defect, if the size of the latter is retained large enough to 
admit of stadia lines so placed as to read 1:100. We often 
leave the field much larger, however, in which case there ap- 
pears just a slight dimness at the extreme border; this is unim- 
portant, for it does not retract any of the virtues of the glass, 
and possesses, if anything, an advantage of finding an object 
more readily. 

The quality of some of the telescopes of our best makers 
has often been questioned by competent engineers on account 
of a peculiar haze ascribed to the glass. This was found to be 
caused by a small film of moisture, which settles between the 
crown and the flint, and is not visible to the naked eye. We 
have been convinced, by advising with our optician, that the 
crown and flint glasses should always be connected with balsam. 
This does not decrease the amount of light, as formerly thought, 
but, on the contrary, it has advantages of clearness, in that it 
prevents foreign matter from settling between the lenses, which 
always destroys the image; the refrangibility, too, is under 
more favorable conditions in the balsam. 



34 MODERN SURVEYING INSTRUMENTS. 

Extra Accessories for the Transit. 

There are a number of additions made for transits used for 
special purposes, and these we keep on hand, and supply them 
when called for. 

For laying off right-angles, for instance, we can make any 
provision, if the customer will order it in time. In fact, any of 
the accessories, not usual in the ordinary complete field instru- 
ment, will be made as an extra if our patrons will notify us. 

For the solar attachment we provide a block with a thread 
on the telescope axis to receive the beautiful little apparatus 
known as the " Saegmuller Solar," of which a complete descrip- 
tion will be found in Part III. 

The Finish. 

This is made to give the instrument an elegant, tasteful 
appearance, without adopting a color glaring to the eye. Our 
instruments are finished in a number of hues, and may be 
bronzed to the special taste of the purchaser, if he chooses to 
order it. 

Size of Transit. 

The dimensions and proportions of the several parts of the 
transit are given in Part IV of this catalogue, where the differ- 
ent sizes and varieties of instruments made are described more 
in detail. 

Packing. 

This is not at all an unimportant feature. Our transit is 
easily taken from the tripod by means of the Lietz friction 
coupling already described, and set upon a wooden slide, to 
which it is fastened by means of two thumb screws and wooden 
clutches — a manipulation requiring but a moment's time. 
Nothing is taken from the instrument except the shade — it re- 
mains a complete whole from the base-plate to the top of the 
telescope. The board slides into the box with the transit in an 
upright position, with the clamps secured to keep it from turn- 
ing. An extra place is provided for the solar attachment, if 
there be one. The door may then be locked, and the instru- 
ment is absolutely safe, with the least effort of packing and ad- 
justing in the box. 



THE A. LIETZ COMPANY. 35 

Rubber cushions are provided at the bottom of the case, to 
take up any sudden jar or jolt to which it may be exposed dur- 
ing transportation. 

A rubber bag, or a silken one, may be had as an extra to 
each instrument, as well as a bottle of fine watch oil for lubri- 
cation of centers, etc., and camel-hair brushes for dusting. 
Likewise are a number of adjusting pins supplied. 

The Tripod. 

We have adopted the new form of split Leg — a construction 
which combines the greatest stiffness and strength with the 
least weight. The old form of the heavy solid leg has long 
since been abandoned, and we no longer make such a tripod, 
unless specially ordered by some conservative customer, or for 
very small instruments. We aim to reduce the weight of every- 
thing, without sacrificing steadiness or strength in any partic- 
ular, and that the split leg meets these conditions better than 
the solid one must stand to reason. 

The very best white ash is chosen and carefully worked. 
Instead of fitting the leg between two brass cheeks, we fit one 
cheek in the leg. In the older construction it frequently hap- 
pened, in drawing the bolts closer to tighten a loose leg, that 
the cheeks would spring the plate, or weaken the screws that 
hold it. This is entirely obviated by the new arrangement of 
these parts, for the tightening can no longer affect the plate in 
the least. While in the former the leg would only fit at the 
lower part of the cheeks when drawn in by the bolt, it will al- 
ways fit the whole surface of the cheek in the plan we follow, 
and after ten years' use it will be just as steady as when new. 

The shoes are made on a gradual taper to a sharp point, and 
securely fastened to the leg. They are provided with a projec- 
tion for pressing upon with the foot when setting up. 

The large transit and the level fit the same tripod — in fact, 
any Lietz instrument may be readily fitted upon the tripod we 
manufacture, for the adjustment of the friction coupling allows 
a perfect accommodation to any slight variation in the parts of 
the base-plate. 



36 MODERN SURVEYING INSTRUMENTS. 

LEVELING INSTRUMENTS. 

The A. Lietz Company manufactures two different varieties, 
which are constantly kept in stock, the Y-level and the dumpy 
level. 

In the manner of making these instruments, much that has 
been said of the transit will hold good here, and need not be 
repeated. 

The three main qualities to be secured in a level are: 
stability, a sensitive bubble and a powerful telescope. 

To secure the first, we need only refer to the solid construc- 
tion of the star-shaped casting through which the leveling screws 
operate, already described in speaking of that feature' in the 
transit. The Lietz coupling, too, plays an important part here, 
for we can make the tripod connection absolutely rigid. 

The center, or spindle, is almost three and one-half inches 
long, and is continued through the clamp up to the bar, which 
enables us to bring the center of gravity as near as possible to 
the tripod head. Great care is exercised in fitting the center to 
the socket, and, being made of steel, it must be apparent that 
it is an utter impossibility to wear out these parts even by fifty 
years' constant use. The liability of bending the spindle, so 
common an accident with instruments having brass centers, and 
the fretting of the same, also likely to happen at times, is al- 
together avoided by a steel center. The fact is, every level 
ought to have one, and its omission is simply due to the fact 
that it is more expensive to manufacture. 

The reasons for having a sensitive bubble have also been 
carefully set forth heretofore. Accurate work cannot be done 
with a sluggish bubble. No matter how much the virtues of 
the staying qualities may be extolled by some men, they are not 
fit for refined work if they do not answer the slightest touch of 
the leveling screw. If you can give a screw a twist or two be- 
fore the bubble loses its peaceful equanimity, the work in hand 
would not be likely to inspire any great confidence. 

Our level tube is curved, so as to give for every two minutes 
of arc a one - inch motion of the bubble. A refined level 
of this character, however, will only do good service in 



THE A. LIETZ COMPANY. 37 

an instrument having perfect steadiness and a powerful and 
sharply denning telescope. If placed in a level so constructed 
as to be topheavy, or in one whose center is frequently exposed 
by being a part of the tripod head — and therefore liable to col- 
lect dust both on the cone and in the socket, introducing sources 
of error after every detachment — then it will indeed prove very 
annoying, should an active bubble accompany such an instru- 
ment. These structural defects are probably the cause why 
many of our engineers are prejudiced against sensitive levels, 
and prefer a sluggish or dull one. We can only assure the 
reader again that a lively bubble, even if a little out of center 
by reversing the instrument, will still accomplish better results 
than an inactive one — one that gives the instrument an appear- 
ance of steadiness, which in reality it is far from possessing. 
An engineer only deceives himself if he trusts to a slowly-acting 
level, which gives apparent satisfaction by concealing the errors 
that a sensitive one would soon indicate. A well-made instru- 
ment never suffers by having its qualities exposed by a high- 
grade bubble. 

The level telescope should have power and definition. It is 
hardly necessary to make that statement, after all that has been 
said on this subject in a previous chapter. It has been our 
earnest endeavor to obtain these results, without increasing the 
dimensions of the telescope and the other parts of the instru- 
ment, beyond the proper limits for steadiness and portability. 
A length of eighteen inches we have found to give the most 
advantageous results. Experience has shown us, that although 
an increased length adds to the magnifying power, it would 
only be of value if the other parts of the instrument were 
enlarged in proportion, which, on the other hand, would make 
it too heavy for convenience in carrying. While in some ex- 
ceptional cases such an instrument might be preferable, we 
believe that with our 18-inch level even the most extensive re- 
quirements in engineering are fully met. 

Our new and improved eye-piece, and the use of an ob- 
jective of larger diameter than ordinarily found, enable us 
to obtain a magnifying power of 33. An increase of diame- 
ter adds very little to the weight of the telescope, and does not 



db MODERN SURVEYING INSTRUMENTS. 

require a longer bar and larger plates, as an increase in length 
necessarily would, to retain steadiness. An aperture of If 
inches, used to its full value, affords a high illumination with 
the above-mentioned power, as the tube is large enough to let 
all the rays proceeding from the object glass pass through to the 
field of view — an important point disregarded by a number of 
manufacturers. 

The diameter of the aperture of the object glass divided by 
the power, gives the diameter of the pencil of light entering the 
eye. In our telescope we obtain, therefore, If -f- 33 = -% T of an 
inch, which shows that power and brightness are in accordance 
with optical law. To force the power beyond these limits we 
cannot conscientiously do, as that would be allowable only 
under certain circumstances — such as a perfectly clear atmos- 
phere with a strong illumination of the object. 

The collars, upon which the telescope rests in the Ys, are 
made of the hardest bell metal, and admit of a position in either 
direction, that is, the telescope is reversible. The very first 
requisite is that these collars must be of exactly equal diameter 
and perfect cylinders. If this be not the case, the line of colli- 
mation will not be parallel to a tangent of the bubble's curve at 
its highest point, when the latter indicates a horizontal position, 
and, for this reason, a true level cannot be obtained with such 
an instrument. 

It is very often believed that in the course of adjusting the 
Y-level, by reversal of telescope and revolving on center, the 
bubble will indicate any inequality of the collars, but this is by 
no means true. If the Ys are both filed out to the same angle 
(this is generally the case, or at least very nearly so, as most 
makers file them out by means of gauges), the inequality of the 
collars may be quite appreciable, and yet the instrument will 
be adjustable in all its parts; in other words, it may be so ad- 
justed that the bubble on all reversals in the Ys and revolutions 
on centre, will always give the same reading at both ends, that 
is, indicate a true horizontal position. A final test is necessa- 
ry, therefore, after the instrument is properly adjusted, to as- 
certain the equality of the collars. This will be mentioned 
further on under the head of adjustments. 



THE A. LIETZ COMPANY. 39 

Similar causes for error are introduced if a particle of sand 
lodges between the collar and Y, which illustrates the necessity 
of keeping these parts free from all dust and dirt. 

It is readily demonstrated to what considerable differences 
any slight inequality in the diameters of the collars may give 
rise to, but the space here will not permit of a mathematical 
discussion of the subject. 

We have carefully explained this defect, owing to the con- 
viction on our part that it is a much more common one than is 
generally suspected. Numerous cases have come under our ob- 
servation, where this fault existed in a remarkable degree. And 
in the perusal of many works on engineering and surveying, 
we have noticed very few that call attention to this material 
defect, and still less that give a correct test for it. 

We are aware that accurate leveling may be done with a 
level out of adjustment, if the utmost precaution is taken to 
have equi-distant fore-and back-sights. But looking at it from 
this point of view, why not use the dumpy level then, instead 
of the more costly Y-level? 

The Finish is made to give the instrument an elegant ap- 
pearance, and yet obtain all the qualities alluded to in a previ- 
ous discussion of the same subject. The telescope is usually 
cloth finished to avoid that unequal expansion of the metal here- 
tofore mentioned. This finish is of a color pleasing to the eye, 
is applied so that it remains intact for a long time, and if some- 
what worn after a long period of exposure, it can be readily re- 
applied without difficulty at a trifling expenditure. The cloth 
finish is a modern feature, and one that is so universally pre- 
ferred, that we have no hesitation in recommending it to our 
patrons as worthy of their consideration. However, we keep in 
stock the bronzed and lacquered, as well as the cloth -finished 
level telescopes, so that the customer may have his choice in 
the matter. 

The level telescope is supplied with a slide protector and 
with a sunshade; the latter should always be put on to balance 
it evenly. A cap is also provided for the objective and a shut- 
ter for the eye-lens. 

In all other matters the transit details obtain here also. 



40 MODERN SURVEYING INSTRUMENTS. 

Fixed stadia reives are supplied, set to read 1: 100, for which 
an extra charge is made. 

The center movement is checked and regulated by a clamp 
and tangent screw, exactly similar to those of the transit. 

Other useful accessories are attached, but any feature not 
usually found in the Y-level, must be ordered beforehand. If 
desired, we place agate fittings in the Ys for the collar contact, 
but for this we also make an extra charge. 

We are likewise in a position to make, but upon order only, 
levels of precision for the most exact work that the geodetic sur- 
veyor is called upon to perform. These are provided with all 
the delicate details that such an instrument must possess. We 
invite correspondence upon the subject of geodetic instruments, 
and will cheerfully furnish prices after consulting with our 
patron upon the nature and character of the instrument re- 
quired. 

The packing in the case has been made so as to assure safe- 
ty in transportation, with the least trouble and inconvenience 
to the operator. The level is taken from the tripod by a third 
of a revolution of the base plate, which undoes the Lietz Coup- 
ling. It is let down to stand upright in the box, the telescope 
having been removed from the Ys and placed with its collars 
upon padded brackets at the side of the case, when the closing 
of the lid holds everything firmly in place. In all minor details 
the level box is similar to the transit case, every means being 
employed to insure absolute safety. 

The Dumpy Level. 

In this instrument the aim has been to construct it in such 
a manner that it shall be as compact as possible by dispensing 
with certain features of the Y-level, not absolutely necessary in 
order to do good and reliable work. 

The principles governing its construction are the same as 
those that obtain in the more elaborate Y-instrument. 

The telescope is permanently held by two vertical arms at- 
tached to the level bar, and cannot be taken therefrom. The 
level tube rests upon these arms, over the telescope, and is also 
fixed. The telescope tube is thereby brought as close as pos- 



THE A. LIETZ COMPANY. 41 

sible to the tripod head, which is a desirable characteristic. All 
the other features remain the same as in the Y-level construc- 
tion. 

This instrument, which is almost exclusively used in Eu- 
rope, has not yet met with that favor by American engineers, 
which its simplicity and accuracy so justly deserve. This is 
due partly to its greater inconvenience in adjusting as com- 
pared with the Y-level, and partly on account of defective con- 
struction, inferior telescope and other neglected details, which 
usually obtain in instruments of this kind. 

We are confident that a dumpy level possessing a good tel- 
escope, sensitive bubble and stability, will do just as good work 
as the more costly Y-level. While the adjustment of the latter 
is made more readily, the former will retain it longer. 

Our dumpy level has a bronze center, a 15 -inch telescope, 
and a vial of such curvature, as to give for each inch of mo- 
tion of the bubble an angle of three minutes. 

There is no clamp or tangent screw to this form unless or- 
dered by the customer. 

Bar, telescope and vial case are cloth finished, and the lat- 
ter may be provided with a folding mirror, which acts as an 
important protection to the more exposed spirit level when shut 
down, or as an indicator to the observer at the eye-piece, of the 
exact position of the bubble, when elevated. 

The stadia hairs may also be supplied to the dumpy level. 

Other Levels on Sale. 

In addition to the high grade instruments manufactured in 
our shop, we keep on hand a supply of smaller and less costly 
goods, imported from Germany. With these instruments work 
may be done by the ditcher, irrigator, contractor, grader, farmer, 
dike builder, gardener, plumber, architect, forester and military 
man, sufficiently precise for many ordinary purposes, wherein 
great accuracy is not required. 

For a more detailed description of these instruments, see 
Part IV of this catalogue, containing a price list of articles on 
sale. 



42 MODERN SURVEYING INSTRUMENTS. 

Remarks. 

In the foregoing we have endeavored to give the reader 
a fair idea of the principal engineering instruments made 
by this firm. We desire to convince our future customers 
— our old patrons we have long since convinced — that we are 
building conscientiously upon scientific principles, that every 
part and detail has been carefully studied to meet the require- 
ments of our engineering fraternity, of the climate, and of all 
those conditions that influence the shape and character of every 
feature of the surveying instrument. It must permit of all op- 
erations at the least expenditure of time, it must be compact, it 
must be light, it must be absolutely accurate, it must be rigid, 
it must be stable and it must possess strength. And wherever 
a possible improvement is suggested in any detail, it must be 
applied at once and tested as to its probable merits, and if it 
prove of value, no time must be lost in introducing it. These 
are the principles that have governed the manufacture of the 
articles which we have brought to your notice. 

New improvements have always had our attention, without 
any regard of the expenses incurred in experimenting. We 
need only refer to the recent introduction of aluminium in the 
manufacture of surveying instruments, which, we are fully con- 
vinced, has been crowned with success, to prove to our patrons 
that we never allow any conservative notion to rule the estab- 
lishment. The particulars of this new field of manufacture 
will be found in another chapter of this part of the Manual. 

With the object constantly in view to make only the very 
best article that can be procured anywhere, and ever ready to 
introduce improvements and to experiment with suggestions 
that may lead to them, our instruments are held at a price that 
is commensurate with their qualities. Their values are rated 
by those current among first-class instrument makers; they are 
no more, but they are no less. We do not handle cheap goods, 
and the trade that we are most anxious to please is that willing 
to pay a fair price for a number-one article. With us the value 
of an instrument depends upon the features involved and the 
accessories supplied, and never upon the workmanship; that is 



THE A. LIETZ COMPANY. 43 

always first-class, from the simplest compass transit to the most 
improved transit theodolite. 

It was our purpose to describe in this catalogue only the 
instruments for which there exists the greatest demand, and for 
this reason we do not intend, at this time, to enter into any 
detail of the manufacture of other scientific apparatus that we 
are in position to furnish upon due notice. 

Theodolites of the highest grade for the most exact pur- 
pose, reading with micrometers to the most refined division, will 
be made upon order to any desired shape and design, and with 
every required accessory. This also holds good for all nautical 
apparatus, such as sextants, three-armed station pointers, logs, 
barometers, compasses, marine glasses, etc., etc. 

We also manufacture the topographer's plane-table, either 
in its simplest form, as recently perfected by the highest author- 
ities, or in its most delicate arrangement of parts, as devised 
for work of the greatest precision capable of being put on paper. 
A number of plane-tables made for our institutions of learning, 
and for surveying departments of the U. S. Government, have 
given absolute satisfaction, as shown by testimonials in our 
possession. 

The modern improved plane-table alidade is a particular 
specialty, to which we have given considerable time and atten- 
tion. This instrument has been constructed by us of aluminium, 
which has been a perfect success, proven by the fact that one 
of them has been almost daily in use for some time, under very 
trying conditions, without giving rise to the first complaint. 
Under the head of Aluminium for Surveying Instruments, this 
will be again referred to. By a combination of aluminium and 
aluminium bronze, the center of gravity of the alidade may be 
brought close to the foot of the standard, which is a very essen- 
tial point in its construction. 

ALUMINIUM FOR SURVEYING INSTRUMENTS. 

A great deal has been said and written about this compar- 
atively new metal of late, so that its characteristics have become 
generally known. 

Its color is a dull white, similar to silver, and rather pleas- 



44 MODERN SURVEYING INSTRUMENTS. 

ing to the eye. It embodies many qualities that make it a very 
valuable material in the mechanic arts. It is quite soft, but 
possesses malleability, tenacity and ductility, so that it may be 
made into very thin sheets, or drawn out into fine wire. It is 
a conductor of heat and electricity. One of its principal feat- 
ures is that it does not oxydize in the atmosphere, and that it 
does not lose its brightness under conditions that would tarnish 
silver and blacken it, for sulphuretted hydrogen or sulphide of 
ammonium do not influence its color. But the greatest ad- 
vantage is its remarkable light weight, the specific gravity being 
only 2.6, or one-fourth of that of silver, and for this particular 
quality its use has been sought in the manufacture of articles 
requiring small weight, ever since the cost of its production has 
justified it. 

One of the many alloys is the so-called aluminium bronze, 
which unites hardness with malleability, and is therefore ex- 
tensively used for many purposes. This alloy, however, gains 
little in lightness as compared with the ordinary metals. 

Since it has been the constant aim to produce field instru- 
ments that shall combine strength with the least practical 
weight, there could not have been found a better application for 
aluminium than in the instrument-maker's art. 

It was necessary to experiment with it in different direc- 
tions, particularly as to the proper alloy — it being much too 
soft in its pure state — that shall give the required tensile strength 
and stiffness, make it workable without fretting, and yet add 
little to its weight. An alloy with silver is now made that fully 
satisfies these conditions. 

One of the principal objections urged against it in the 
manufacture of surveying instruments is, that on account of 
extreme lightness they would not be steady enough in the 
wind. This firm has built a number of transits and levels of 
aluminium, and, in our opinion, they are quite as rigid as any 
other, if properly constructed, care being taken to adhere to the 
old material in such details where it cannot be dispensed with. 
We have found that the stability of an instrument depends 
more particularly upon the construction of its lower parts. If 
the combination of base-plate and leveling apparatus be made 



THE A. LIETZ COMPANY. 45 

so that the instrument can be rigidly held, a little more or less 
of wind surface is not so important, as long as every part is 
equally strong. The center of gravity, too, may be brought 
down a little lower, and that in itself would tend to increase 
its stability. 

Aluminium transits are made by the A. Lietz Company in 
two sizes, being complete field instruments with every accessory. 
The large transit weighs 7 h pounds, and the small one 4 J pounds, 
which reduces the weight about one-half. The construction is 
precisely the same as in the instruments already described. 

The base-plate is of composition metal, the inner center of 
the hardest bell metal, and the outer center of bronze. The 
leveling screws are also of composition, as well as the bearings 
of the telescope axis. That means, that wherever any part is 
subjected to particular wear and friction, the old metal has been 
retained, while all the rest of the instrument is made of alum- 
inium. 

These transits may either be left in the beautiful natural 
color of the metal, or other shades may be applied. The stand- 
ards are cloth-finished. 

The Saegmilller Solar Attachvient is now made of aluminium, 
which can only be an improvement in any direction, whether 
its weight be added to the top of a transit made of the old red 
metal, or to one of the new metal. Lightness in the solar at- 
tachment is a very desirable feature, and that may be easily 
obtained now. 

In the Y-level the base-plate and leveling screws are of 
composition metal, the centers steel, the collars the hardest bell 
metal, and the rest aluminium. It has an 18-inch telescope, 
its weight being 5-J pounds. 

In the dumpy level the same features obtain, except that the 
centers are of hard bell metal. Its length of telescope is 15 
inches, and its weight 4h pounds. 

Both levels are cloth-finished, similar to. those already de- 
scribed. 

We also manufacture a plane-table alidade of aluminium, 
with a ruler of aluminium bronze. This instrument, although 
of the same weight as one of the ordinary metal of the same 



46 MODERN SURVEYING INSTRUMENTS. 

size, possesses the particular advantage of having its center of 
gravity as low as it can possibly be brought to the table, and 
that when placed upon the board it will be absolutely stable, 
and will not be influenced by the wind, which causes the ordi- 
nary alidade to tremble and travel on the paper. 

We are firmly convinced of the adaptability of aluminium 
for surveying instruments, and for that reason our firm has 
gone extensively into that branch of manufacture, for which 
every facility has been added recently to the capacities of the 
shop. The aluminium instrument is fifty per cent, lighter 
than the other, is just as strong, is just as precise in its work- 
ings, possesses every requisite detail of a complete field instru- 
ment, and, we claim, is just as stable. Those of the engineering 
fraternity who have to carry the transit all day, the mining and 
railway men, who climb the mountain sides during the long 
summer days from early until dark, will not be long in finding 
out these advantages and in putting them to a severe test in 
every direction. 

CARE OF INSTRUMENTS. 

The greatest source of danger to a delicate instrument is 
careless handling. It is often subjected to violent usages for 
which there is absolutely no need. The rude way of manipu- 
lating its delicate parts; the unnecessary display of digital 
strength in operating a clamp; the useless strain applied to the 
leveling screws; the careless manner of carrying it; the rough 
method of taking it out of its case, or replacing it; and the in- 
cautious closing of a lid or door of a box by force, before the 
instrument is somewhat adjusted to its position; all these are 
sources of danger that vitiate its adjustments and cause no end 
of trouble and expense. Although a well-made instrument is 
so designed as to stand many a shock without direct injury, any 
daily repeated abuse is sure to have its ill effect, from which 
your work must suffer. Our warning to be careful in the 
handling of your instrument, is therefore a well-intended piece 
of advice. 

As the usefulness of a transit or level may be preserved for 
many years by a little attention to details, we shall enumer- 



THE A. LIETZ COMPANY. 47 

ate a few of the principal points which the engineer will do 
well to observe. 

Always protect your instrument from rain by throwing 
over it a waterproof bag; and if it gets wet at all, clean it 
thoroughly after getting under shelter. It is not well to enter 
a hot room from the cold air, without giving it some protection. 
The condensing vapor settling on the metal and glasses is certain 
to give rise to injuries. It is always safe to place the instru- 
ment in its case before going into a warm room in winter. It is not 
wise to leave your transit or level exposed for hours to the hot 
sun. Shade must be given either by a hood thrown over the 
instrument, or by holding an umbrella. Attention to these 
points will preserve the accuracy of all the delicately adjusted 
parts, that by an unequal expansion or contraction would be 
certain to suffer. 

But, accidents are liable to happen, and for that reason we 
have noted down a few remedies in case of an emergency. 

The general tendency in the use of the screws is to over- 
strain them. This should never be done, especially with the 
cross-wire screws, which, when brought up too tight, are liable 
to constant change and loss of adjustment. The leveling and 
clamp screws, if overstrained, wear out sooner and may show 
fretting. If this takes place, they should be taken out and 
brushed with a little coal oil or benzine. The nuts are best 
cleaned by screwing a flat piece of soft wood through their ap- 
ertures. In putting them together oil them slightly. 

Fretting of the centers and of the telescope-slide will inter- 
fere more with a correct working of the instrument than any 
other part out of order. They should be watched, therefore, 
very closely, and as soon as any rough motion manifests itself, 
it should be remedied at once, if possible, by an instrument 
maker. If this cannot be had, and the fretting is in the slide, 
first scrape and then burnish down the place where it frets. It 
may also be ground slightly with oil and very fine pumice stone 
dust, which is best obtained by rubbing two pieces on each 
other. After grinding them a little, the tubes should be 
cleaned and placed together again with oil only; then move 
them in and out a number of times, wipe the oil off, and 



48 MODERN SURVEYING INSTRUMENTS. 

finally put them together when dry. Should the fretting 
occur in the centers (if properly made and constructed, so 
that they do not come apart in detaching the instrument 
from the tripod, this will never happen), employ the same 
means; and if this be not effective, place a washer, made of 
paper or a thin card, between the shoulders. This will 
cause a shake, making accuracy impossible, and will introduce 
errors of parallax in reading off, which is better, however, than 
to destroy the centers wholly. The best unguent for them is 
very fine watch oil. Regarding our centers, we are fully pre- 
pared to assure our customers that no fretting will ever happen, 
as they are never exposed, and made with the utmost care. 

The object-slide should not be oiled. Never, under any 
condition, use emery in trying to repair an instrument, as it 
cannot be removed again and will grind continually. 

An efficient lubricant for leveling screws, clamps, pinions, 
etc., is well rendered marrow. 

If an instrument is upset, thereby bending centers and 
plates, do not turn it unnecessarily, as this will disfigure the 
graduation, but send it to a competent instrument maker im- 
mediately. There should be no delay in repairing defects. 

In the matter of the tripod, it is wise to look to the screws 
that hold the legs frequently, and to keep them well tightened 
up; and to inspect the shoes, to see that they do not come loose. 
An instrument cannot be steady if there is any shake in the 
tripod, which is its support and must be firm in every particular. 

The graduation is a very delicate detail to handle, and 
should be approached only with the utmost care. It is safe to 
leave this part to the instrument maker, and not to attempt to 
remove the plates, as they cannot be properly re-centered with- 
out the aid of a testing apparatus. An exposed graduation 
may be cleaned with a little watch oil and a. chamois skin. 

To preserve the sensitiveness of the needle, the center pin 
must be prevented from becoming dull. The instrument should 
never be lifted without raising and arresting the needle, and if, 
upon letting it down again, the swing is too large, gently stop 
it when within a few degrees of its natural bearing. Every 
check and start must be made gently, never abruptly. Should 



. 



THE A. LIETZ COMPANY. 49 

the point become dull, it is best to send it to an instrument 
maker; if this be not practicable, a watchmaker may perhaps 
attend to it. It should be remembered, however, that the point 
of poise must be centered — that is, occupy the center of the 
graduated circle. This cannot be done by a watchmaker, and 
is only to be relied upon if made in an instrument maker's 
shop. 

If a needle is made of good steel, well hardened and prop- 
erly charged, it will not often lose its magnetism; and if, when 
placed away, it is always brought to lie in the meridian, it will 
retain, or even increase its polarity. If a needle has lost its 
magnetism it may be charged again with an ordinary horse- 
shoe magnet; one of three inches in length will be suitable for 
this purpose. The operation is this: hold the magnet with the 
poles upward, then, with a gentle pressure, pass each pole of 
the needle from center to extremity over the opposite pole of 
the magnet, describing before each pass a circle with a diameter 
of about double the length of the needle, taking care not to re- 
turn it in a path near the pole. If the magnet is strong enough, 
the needle need not be taken out at all, but by raising it against 
the glass and then passing the magnet over this, it will be 
charged sufficiently. After charging, the needle has lost its 
balance, which may be easily restored by shifting the brass wire 
on the south end. 

The observer should always satisfy himself that there be 
nothing about his clothing, especially in the make of the but- 
tons, that would have any influence upon the needle. 

In the matter of the telescope, intelligent handling will do 
much towards preserving its accuracy and reliability for a long 
time. In cleaning any of the lenses, use a soft rag or chamois 
leather. If the glasses should become greasy, or very dirty, 
wash them with alcohol. The inner faces will seldom require 
cleaning, and it is not advisable to take the telescope apart too 
often, as it is likely to destroy its adjustment. If dust should 
settle on the cross-hairs, it is safest not to touch them. The 
only remedy that may be tried is to take out both the object- 
glass and the eye-piece, and to blow gently through the tube. 
This may remove the dust without injuring the threads, but it 
is quite a delicate operation 



50 MODERN SURVEYING INSTRUMENTS. 

Cross-hairs may be replaced in the field by the engineer. 
The spider web is cleansed from dirt by placing it in water for 
a few minutes. A little manipulation readily removes any 
particle that may adhere to the thread. After drying for a 
moment, adjust it to the diaphragm, previously cleaned from 
dust, and attach it by means of a little shellac. It requires 
considerable practice to do this nicely, for a spider's web, al- 
though quite strong, cannot be handled by clumsy fingers with- 
out parting; but in the case of an emergency the engineer must 
try to do the best under all circumstances. 

Referring again to the lenses, it is well to remember that 
in taking them apart, the centering is disturbed, and the engin- 
eer is not able to replace them properly, especially if they fit 
loosely in the cell, which is very often the case. The staining 
of flint-glass lenses is caused by the corrosion of the oxide of 
lead contained in the glass. This will generally occur when 
the lens is kept in a damp place for some time. In cleaning 
an object-glass, care should be taken not to rub it any more 
than necessary. Brush off the dust first with a camel-hair 
brush, and then wipe it carefully with a clean piece of chamois 
leather. If very dirty, Avash it with alcohol or water and soft 
chalk, being careful to have the latter free from grit. 

Considering that, in cleaning, each rub will destroy more 
or less of the fine finish of the lens, upon which depends the 
brightness and brilliancy of the image, the surveyor will be 
well repaid for his care in this particular. 

Similar attention must be bestowed upon the eye-piece. 
With our high power eye-pieces, a motion of only three-six- 
teenths of an inch is necessary to allow for difference in eyes. 
As the sliding motion is for this purpose alone, it is not at all 
necessary to disturb it after it has once been properly adjusted, 
as long as the same person is using the instrument; even in 
packing it away in the case the eye-piece may be left so, as this 
extra extension is allowed for in the box. The cap is provided 
with a slide to protect the eye-lens from dust while the instru- 
ment is not in use; the engineer should never neglect to close 
this, and to cover the object-glass with its cap as well, as soon 
as the instrument is set at rest. 



THE A. LIETZ COMPANY. 51 

REPAIRS. 

We are fully prepared to make careful repairs to all instru- 
ments, from the graduation of an arc or circle, and the straight- 
ening of a center or plate, to the setting of a simple screw. In 
this particular branch we have operated here for the last ten 
years, and have gained the fullest confidence of our people. 
Attention has already been called in the first part of this 
Manual to the first-class facilities that we have for making re- 
pairs in any line — mechanical, optical, nautical or otherwise — 
and for that reason we need only state here that Ave guarantee 
satisfaction to our customers in every way. 

As we are located in California, separated by the breadth 
of the Continent from our Eastern colleagues, we are necessarily 
required to repair instruments of almost every known make, 
and this has compelled us to procure the various requisites in 
the workshop, for all emergencies. To-day we are in the posi- 
tion to renew any part of an instrument, no matter where it 
was originally manufactured. Time and money will be saved 
by sending directly to us, and we shall try to give our custom- 
ers every satisfaction. Whatever is entrusted to us will be 
thoroughly overhauled, and put in the best possible condition, 
unless specified orders are received to confine the repairs to 
certain details. As a general thing it ought to be left to our 
judgment as to what the instrument requires; it may cost a 
little more if you follow our advice in this particular, but it will 
certainly be more satisfactory in the end. It will save time, 
trouble and additional expense. In the course of our examina- 
tion of an instrument needing repairs, we discover defects that 
could not be apparent to anyone, before its parts were separated 
and individually tested. What may appear of no consequence, 
and is therefore neglected, is quite likely to lead to all sorts of 
subsequent inaccuracies in your work. Years of experience in 
this particular line have taught us the advisability of urging 
this point upon our patrons. 

Considerable correspondence is had from inquiries about 
the cost of repairs. Although it is impossible to state the exact 
figures before an examination, there are certain rates for ordi- 
nary repairing that we may mention here. 



52 MODERN SURVEYING INSTRUMENTS. 

The most expensive instrument in this regard is the transit, 
being the most complicated in parts. If injured by a fall, new 
centers and a new telescope axis are generally required, the cost 
varying from $10 to $30, reaching sometimes as high as $50. 
If slightly injured it will vary from $5 to $10. 

Injuries sustained by leveling instruments are generally 
less serious. A new level vial costs from $2 to $7.50, according 
to size and sensitiveness. Instruments defective in construc- 
tion or workmanship will not require a sensitive level, as that 
would be a source of constant annoyance to the engineer; the 
bubble should be chosen to harmonize with the general qual- 
ities. As a rule, we attach to the better class of instrument a 
level that shall give for each inch of motion of the bubble an 
angle of two minutes; to the inferior grade, one of three or four 
minutes. 

Compasses sent to us are generally injured by the dulling 
of the center pin. Sometimes the plates and sights are bent 
and the glass broken. Often the center cap is worn out, and a 
new one is required. The cost of repairing ranges from $2 to 
$8, and even as high as $10. A new needle, having the largest 
breadth in a vertical direction, which is far superior to the flat 
style, costs $5. A new center pin, 75 cents. New center cap 
with jewel, $1.50. 

Careful re-adjustments made under the collimators are 
charged for at the rate of $2.50 for each instrument. 

Transits and levels should always be accompanied by the 
leveling plates; the tripod and head need not be sent. With 
compasses the ball spindle should be sent. 

We advise our customers to pack their instruments care- 
fully, when sending them to us for repairs, as they are liable to 
material injury if this precaution be neglected. The space in 
the box between the different parts — of the transit particu- 
larly — may be filled with soft paper wads to protect it from 
jars and blows. It is well to put the case in an additional box, 
a little larger in dimensions, in such a manner that the top of 
the case is plainly visible and its leather strap handy for carry- 
ing. The space between the case and the box may be padded 



THE A. LIETZ COMPANY. 53 

with shavings, or some soft material to take up the shocks. 
Mark upon the top of the box in large legible letters: 



|CS^ This Si de Up ! ! ! 

Scientific Instrument. 

Handle with Care ! ! 



And ship through a responsible express company, plainly ad- 
dressed to: 

THE A. LIETZ CO., 

422 Sacramento Street, 

San Francisco, Cal. 

The name of the sender and his address, together with the value 
of the instrument, should also appear on the box. 

This will insure comparative safety in transportation, which 
is a point that should be well observed by the engineer. And 
this precaution would also increase the responsibility of the 
carrier, in case the instrument had suffered during transporta- 
tion. 

When an instrument is sent to us for repairs, a letter or 
postal card should be mailed at the same time, to inform us of 
the fact, giving the necessary directions, and stating when the 
return is required. The receipt of the instrument will be ac- 
knowledged by us at once. 

ADJUSTMENTS. 

Adjusting an instrument consists in delicately moving to 
the right or left, and up or down, certain parts that must be 
either parallel or at right-angles to each other. This is done 
by slightly turning a number of capstan-headed screws or nuts 
by means of a small steel rod, called an adjusting pin. Adjust- 
ing the vernier and compass consists in placing certain points 
in a straight line; but as these corrections are always made by 
the instrument maker, they do not properly apply to the sub- 
ject before us. Verniers, limb and needle, if properly placed at 
the outstart, will not need any correction in the ordinary use. 



54 MODERN SURVEYING INSTRUMENTS. 

Of the Transit. 

1. Adjustment for Parallax. — This is a very essential 
one, and must be looked to carefully in every surveying instru- 
ment, whether transit, level or theodolite. It consists in so 
focusing the eye-piece that the cross-hairs shall stand out dis- 
tinctly and well-defined, when the telescope is directed upon an 
object in focus. If this is not properly done the hairs will be 
dim; they will appear to travel and to seem unsteady when set 
on a mark. We know that this has given considerable vexation 
to the observer, and instruments have been disparagingly con- 
demned for their apparent parallax, when nothing more was 
necessary than a slight movement of the eye-tube to focus the 
hairs properly. This fact should be well borne in mind. Our 
eye-pieces are quite easily moved in or out by a revolving mo- 
tion, which affords a very fine and precise adjustment to focus. 

Operation. — Direct the telescope so as to have a clear view 
of the sky, and then turn the eye-tube by the cap as just de- 
scribed, until the cross-hairs stand out like two sharp and dis- 
tinctly drawn black lines. After a few trials this is accomplished 
without difficulty. Then try the telescope upon some object 
brought into focus and test the clearness of the wires. A point 
now bisected must stay so while the eye is moved laterally in 
front of the eye-hole. If it remain stationary, there is no par- 
allax and the adjustment is made. Once properly set, the eye- 
piece may remain for the same observer for all time, and need 
not be adjusted from day to day. Attention has already been 
called to this point in a previous chapter, where it was noted 
that the instrument box was made large enough to allow the 
eye-piece to extend beyond the tube. (The sun-shade should 
be put on the telescope first, and then focused to mean distance 
to balance it properly.) 

2. Plate Levels. — The object is to set the levels at right- 
angles to the vertical axis of the instrument, so that when the 
bubbles are centered the axis is truly vertical. 

Operation. — Bring the bubbles to the middle of the tube by 
means of the leveling screws, then turn the instrument on its 



THE A. LIETZ COMPANY. 55 

center 180 degrees. If they remain central for any position, 
they are in adjustment; if not, they must be elevated or de- 
pressed at one end to correct them. One-half of the required 
correction is made with the capstan-headed screws on the vial 
case, the rest by the leveling screws of the instrument. Several 
repetitions of the operation may be required before attaining 
accuracy. It is well to have the plate in such a position, that 
the levels shall be parallel to a pair of opposing foot screws. If 
they are out considerably, it is better to adjust one first, approx- 
imately, and then the other. 

3. The Standard Bearings. — The telescope should re- 
volve in a vertical plane when the instrument is level. One 
end of the telescope axis must be either raised or lowered until 
accuracy is reached. A capstan-headed screw is attached for 
that purpose. 

Operation. — Set the instrument up within about fifty feet 
of the wall of a house. Take a well-defined point as high up 
as possible on the wall; clamp and bisect; then turn down the 
telescope and put a point in line as low on the wall as may be 
conveniently reached. Reverse the telescope and direct again 
to the upper mark, if you please; clamp and bisect; turn down 
to the lower mark, and if it is bisected, the telescope revolves 
in a vertical plane and requires no adjustment. If it does not 
strike the point absolutely, one-half of the difference is taken 
up by the capstan-headed screw, and the adjustment is done. 
Several repetitions of the operation may be required. It is not 
necessary to level the instrument, but it should be brought in 
such a position as to admit the bisecting of two well-defined 
points. Care should be taken, however, that the observation is 
made at the intersection of the cross-wires, and that the instru- 
ment is securely clamped. 

This adjustment should always be made before that of the 
cross-wires, for this reason: that unless points of equal height 
are taken in the subsequent adjustment of the vertical hair, it 
will only then prove correct, if the telescope revolve in a truly 
vertical plane. It is, therefore, always better to look to this 
before the cross-hairs are adjusted. 



56 MODERN SURVEYING INSTRUMENTS. 

This adjustment may also be made by means of an accurate 
striding level, such as manufactured by this Company for use 
in high-grade instruments. The transit must be precisely lev- 
eled up by the foot-screws and plate bubbles, after which the 
striding level is placed aoross the telescope, resting upon its 
axis. It is evident that the bubble will indicate any deficiency 
in the horizontal parallelism of this axis, and, therefore, any 
error in the true vertical motion of the telescope, which may be 
corrected until the bubble of the striding level remains centered. 

4. The Cross-wires. — The line of collimation should be 
at right-angles to the axis upon which the telescope revolves. 

Assuming that all the required conditions have been ful- 
filled by the instrument maker — having placed the telescope in 
the center of the instrument, and having the tubes perfectly 
straight and normal to the telescope axis, which are necessary 
instrumental requirements, there are two methods that may be 
employed. One is by means of back- and fore-sights, which is 
that generally used: the other consists of a test by means of 
three points in a range, where the middle one is occupied. 
Preceding either method the hair should be made truly vertical, 
so that either the upper or lower end will bisect a point when 
the telescope is moved up and down. This is easily done by 
loosening the diaphragm and turning it slightly in the required 
direction. To accomplish this the instrument must be leveled 
up. 

Operation, First Method. — Occupying a point, direct the 
telescope to some well-defined mark, about four hundred or five 
hundred feet distant; clamp and bisect it; then revolve the tel- 
escope and place a point in the opposite direction at about the 
same distance. Now unclamp and turn the instrument half- 
way around; set the hair again on the first point, revolve the 
telescope and sight to the second point. If the intersection bi- 
sects the latter, the vertical hair is in adjustment. If not, the 
error can be corrected by the capstan-headed screws, which 
afford a lateral motion of the diaphragm. With them the ver- 
tical thread should be moved one-fourth of the space intercepted 
between the direction of the telescope and the direction of the 



THE A. LIETZ COMPANY. 57 

second point. Several repetitions may be necessary to obtain 
accuracy. 

The reason why only one-fourth of the space should be 
corrected for, becomes evident from the fact, that in the first 
revolution of the telescope the error of the hair is doubled; and 
after reversing the instrument and revolving the second time, 
it is again doubled, but on the opposite side, so that the true 
direction lies exactly half way between the two, and to correct 
for it we must move the hair one-half the space between the 
true line and one of the points. 

It is not necessary to level the instrument in order to make 
this adjustment; but in case it is not leveled up, the observa- 
tions must be made exactly at the intersection of the cross-wires. 

It must be remembered that the image at the cross-hairs is 
inverted, and that in consequence the screws must be moved in 
apparently wrong directions. 

If there is any lost motion in the tangent screw, great care 
should be exercised in handling the telescope, so as not to in- 
fluence its alignment. 

Operation, Second Method. — Locate with the telescope three 
points in one direction, which are necessarily in a straight 
line, as long as the vertical movement of the telescope is in ad- 
justment. Occupy the middle point with precision, and bisect 
one of the end points; revolve the telescope and sight at the 
other end point. If this is bisected, the instrument is in ad- 
justment; if not, correct for it by taking up one-half the error. 
This method requires leveling of the instrument. 

Thus far we have been speaking of the vertical hair only, 
as it is the more important in a transit telescope. In a plain 
transit — that is, one without a telescope level and without a 
vertical arc — the horizontal thread simply serves to define the 
middle of the vertical one, so that the observation may always 
be confined to a particular point in the latter. But if a level is 
attached to the telescope, then the horizontal hair should be 
brought into the optical axis, before the level is set parallel to 
the line of collimation; otherwise, though adjusted for long 
distances, it will fail to be correct for short sights. 



58 MODERN SURVEYING INSTRUMENTS. 

Operation. — Set up the instrument near a house or fence 
and level up carefully. Clamp the telescope, and by means of 
its tangent screw bisect a point several hundred feet distant; 
then turn on center and mark a point on the house or fence, 
about ten feet distant. Now unclamp telescope, reverse it, re- 
volve on center, and again bisect the nearest point. Turn 
instrument on center and see whether the hair intersects the 
further point. If it does not, the correction must be made, by 
lifting or lowering the diaphragm by means of the upper and 
lower capstan-headed screws, until the bisections, after repeated 
trials, will coincide. 

5. The Telescope Level. — The object of this adjust- 
ment is to make the level parallel with the line of collimation. 
The principle underlying the method is: that points taken with 
the same angle of elevation or depression, and equally distant 
from the instrument, are of equal height. 

Operation. — Set up on a nearly flat surface and level care- 
fully. On opposite sides, at equal distances, drive two stakes 
giving the same level-rod reading, with the telescope bubble 
centered in each instance. These points are necessarily on a 
level with each other. Now move the instrument to a point in 
line with both, and about ten feet distant from one. Level up 
again. Take a rod reading on the nearer and then on the 
further stake. If they agree, the level is in adjustment; if not, 
move the telescope with its tangent screw over nearly the whole 
error, and sight again at the nearer stake and then at the 
further, repeating this until the readings are the same on both, 
when the telescope is truly horizontal. Now bring the bubble 
in the center of the tube by the correcting screws of the level, 
and the adjustment is completed. 

This adjustment may also be made in a room with the aid of 
a surveyor's level, with absolute accuracy. 

Operation. — A few feet (one or more) from each other set 
up the transit and level, each directed to the other. The cross- 
hairs of the level must be illuminated by a light, so that they 
shall become plainly and clearly visible through the transit. 
For this purpose cover the eye-end of the level with a bit of 



THE A. LIETZ COMPANY. 59 

white paper and place a lamp behind it. Focusing both in- 
struments properly will make the hairs appear very distinctly. 
Now, if both instruments are properly collimated, the level 
carefully leveled up, and the transit telescope of such height 
that we may view the interior of the level's tube, we are ready 
to adjust the transit telescope to a level plane, which is done 
by simply placing the intersection of its cross-hairs delicately 
over the intersection of the level's cross-hairs. All that is re- 
quired after that, is to center the transit's level bubble by means 
of the proper adjusting screws. 

This method recommends itself on account of its extreme 
simplicity. 

6. Zero of Vertical Arc. — This adjustment, once made 
by the instrument maker, is seldom vitiated. The object is to 
have the zero line of the circle agree with the zero mark of its 
vernier, when the level of the telescope indicates a horizontal 
position, and when the centers of the instrument are truly 
vertical. 

Operation. — The instrument must be carefully leveled by 
the small plate bubbles, and then the telescope by means of its 
level. This accurately accomplished, the vernier is shifted 
until the zero lines coincide. This must be carefully done, so 
that the instrument is not disturbed, and, when the vernier is 
fastened, care must be taken to allow a space that shall neither 
be too small nor too great between it and the vertical circle. 
In the first case it would bind under certain conditions of tem- 
perature, and in the latter the observer would not be able to 
obtain an accurate reading. The coincidence of the zero-lines 
must be made with a magnifying glass, and all parallax avoided. 

7. Centering the Field of View. — On some transit 
telescopes there will be found another set of four capstan- 
headed screws, exactly alike to that which regulates the cross- 
hair diaphragm, and placed in a position quite close to it. 
These screws are for the purpose of directing the tube of 
the eye -piece in such a manner that the field of view may 
be divided by the cross - wires into four uniform quadrants; 
that is, they enable the operator to so adjust his field that it may 



60 MODERN SURVEYING INSTRUMENTS, 

be bisected horizontally and vertically by the threads. In the 
Lietz transits this adjustment has been omitted, for the reason 
that the tubes are made of such length and with such care — 
being absolutely straight — that there is no need of displacing 
the field, after the line of collimation has been made to agree 
with the optical center, and the hairs are properly adjusted. 
The lines can never appear noticeably out of the field in our 
transits, and any additional movement in the parts of the tel- 
scope would neither be useful nor desirable. A first-class transit 
instrument can dispense with this arrangement altogether, and 
for this reason it is not usually found there. With an extra 
long telescope, however, there would be a slight advantage in 
being able to direct the field of view, for a possible fall of the 
instrument may so injure the tube that it could not be made 
absolutely straight again afterwards, and in consideration of 
this, we have adopted this correction only in the case of the 
18-inch Y- level, which is the most liable to be damaged in that 
way. It alone possesses two sets of capstan-headed screws near 
the eye-end of the telescope — one for the adjustment of the 
cross-hairs, and the other for shifting the field of view so that 
it shall appear equally divided by them. 

Of the Y- Level. 

There are three principal adjustments. The spirit level 
must be parallel to the axis of collimation; it must be at right- 
angles to the vertical axis of the instrument; the axis of colli- 
mation must agree with the optical axis. 

There are other instrumental requirements which belong 
to the instrument maker, however, and it is with the above 
three adjustments only that the surveyor has to deal, as they 
are likely to become disturbed in time. 

Before examining the adjustments, the sun-shade should be 
placed on the telescope, as it is only accurately in balance with 
this. 

1st Adjustment. — To set the spirit level parallel to the line 
of collimation, and, at the same time, place its axis in a plane 
with that of the telescope. It is best to attend to the latter first. 

Operation. — Turn the telescope so as to stand over two op- 



THE A. LIETZ COMPANY. 61 

posing foot-screws, clamp the instrument and bring the bubble 
to the center of the tube; then rotate the telescope in its Ys, so 
as to put the level considerably out of a vertical — say about 15 
or 20 degrees. If the bubble changes its position, it shows 
that the axis is not in a plane with that of the telescope. Cor- 
rect it by moving the two side screws of the level case, until 
one-half of the deviation has been taken up. A few repetitions 
will insure accuracy, and destroy the side motion of the level. 

The level must now be made parallel with the line of the 
bottom of the collars. 

Operation. — Bring the bubble to the center of the tube; 
then reverse the telescope in the Ys end for end; do this care- 
fully. The displacement of the bubble, if there be any, is the 
double error, which is corrected by taking up one-half of it by 
means of the adjusting nuts on the level case, and the other 
half with the leveling screws of the instrument. This opera- 
tion is repeated until the bubble remains in the center. 

To accomplish a proper adjustment of the level to the line 
of collimation, it becomes absolutely necessary that the collars 
be of equal diameter. We have already referred to the import- 
ance of even collar dimensions, and have laid great weight upon 
this requisite; and here again we shall point out the errors to 
which a neglect therein may lead. A Y- level in such an event 
is not any better than a dumpy, and will have to be adjusted as 
such. 

Providing the Ys are filed out to the same absolute angle, 
the instrument may still be adjustable in all its parts: — the 
spirit level may be made parallel to the line of the bottom of 
the collars; the Ys may be so adjusted that the bubble will re- 
main in the center of the tube; the line of collimation may be 
brought to the center of revolution of the telescope; and this 
reversed end for end in the Ys, leaving the bubble in the mid- 
dle, even if there be some difference in the diameter of the 
collars. It is the general opinion that after level, Ys and cross- 
wires are adjusted, the instrument must be correct. This is by 
no means certain, as the least difference in the size of the col- 
lars will throw out the line of collimation considerably. This 
difference is sometimes found in new instruments, and is also 



62 MODERN SURVEYING INSTRUMENT-. 

produced by unequal wear, denting, etc. It is therefore ad- 
visable that the equality of the collars should be tested from 
time to time, which is done by a method given further on. 

2d Adjustment. — To place the level at right-angles to the 
vertical axis of the instrument. 

Operation. — Turn the instrument so that the telescope shall 
stand over the line of two opposing leveling screws, and bring 
the bubble to the center of the tube: then turn the instrument 
180 degrees on its center. If the bubble shows any displace- 
ment, correct one-half of it by means of the nuts under the 
bar at the Y supports, and one-half by the foot-screws. Several 
trials will make the correction perfect. 

3d Adjustment. — To place the cross-web in the optical 
axis of the telescope, so that the intersection will remain on an 
object in revolving it. 

Operation. — Set the intersection of the hairs on a point 
about two hundred or three hundred feet distant, then revolve 
the telescope in its Ys half-way. so as to haA'e the level case on 
top. If the wires have moved from the point, bring them back 
one-half of the amount of the displacement. Try again, and 
repeat the operation if necessary. 

The eye-piece may then be properly aligned and directed 
by the four black capstan-headed screws | nearest the eye-end of 
the telescope), so that the held of view shall appear evenly di- 
vided by the cross-hair-, as already explained. 

In this, as well as in any other telescope, wc assume that 
the tubes are straight, the object-glass well centered, and the 
slide well fitted. If such be not the case, the telescope can only 
be adjusted for certain distances. It is urged by suuie makers 
that it is almost impossible to produce straight tubes, and that, 
therefore, the object-slide must be adjustable. This, however, 
is entirely erroneous. Perfectly straight tub - be made, if 

the necessary time and money be expended, which is the only 
requisite. In a great many instruments sold to-day. you will 
find that the object-glass is not centered, that the slide is poorly 
fitted, and that all these inaccuracies, which are not apparent 
at a glance, prove more injurious than ever if the tubes are not 



THE A. LIETZ COMPANY. 63 

quite straight. It must also seem clear to any one, that the 
constant working of the slide in an adjustable ring would loosen 
the screws and cause considerable annoyance. 

Parallax is adjusted by moving the eye-piece in or out 
until a clear and distinct view of the cross-hairs is obtained, as 
in the case of the transit already described. 

The Collar Test. — After the instrument is properly ad- 
justed, the equality of the collars may be ascertained in the 
following manner: 

Operation. — Make two bench-marks, place the instrument 
exactly midway between them, and find their true difference of 
level by reading leveling rods set upon them. Now place the 
instrument near one of the bench-marks and read the rods 
again. If the difference of the readings is equal to the true 
difference of level, the collars are of equal diameter, and the 
line of collimation is at right-angles to the vertical axis of the 
instrument. This test, once made, holds good ever after, as it 
shows that the collars are true, and consequently that a correct 
adjustment is assured of all its other parts, as already described. 
But it need hardly be mentioned that denting, the settling of 
sand particles and unequal wear will also affect the adjustment 
in the same manner. 

If the test shows that the line of collimation is not perpen- 
dicular to the line of the vertical center, then the collars are of 
unequal diameter, and the instrument is really nothing more or 
less than a dumpy level, as this defect deprives it of all the ad- 
vantages for an easy and convenient adjustment, which charac- 
terizes the Y- level in comparison with the dumpy. 

This defect may, however, be temporarily remedied or 
adjusted in the same manner as the line of collimation in the 
dumpy level is adjusted, but it must ever thereafter remain 
permanently in its Ys, as it would, if reversed end for end, 
double the error which existed previous to this adjustment. 

The correction may also be made by displacing the hori- 
zontal cross-hair to the extent that the line of collimation shall 
be truly horizontal and, at the same time, parallel with the axis 
of the spirit level; but, in that event, there will be no longer 



64 MODERN SURVEYING INSTRUMENTS, 

any agreement with the optical axis, which again gives rise to 
a number of inaccuracies that cannot be obviated. 

A Y- level, in order to deserve that name at all, must have 
equal diameters of its collars; and if that is not found after a 
crucial test, the instrument maker should be called upon to 
remedy this discrepancy. 

Xo doubt can possibly exist in the mind of any engineer 
of the absolute necessity of the collar test. Considering the 
required parallelism of the axis of collimation and the axis 
of the spirit level, he must know that a contact can only be made 
between telescope and Ys by means of the collars, whose ex- 
teriors may either be parts of the surface of a cylinder, or that 
of a cone, and that the required parallelism is only possible in 
the former case. If one collar exceed the other in diameter, 
the centered level bubble, if reversed in the Ys, will indicate a 
displacement corresponding to four times the angle intercepted 
between the collar axis and that of the spirit level. Xo further 
demonstration of this fact is necessary. 

Of the Dumpy Level. 

In principle, the same laws govern the requirements of the 
dumpy that hold good in the Y- level. Although its construc- 
tion differs, the condition of its line of collimation, optical 
center and level vial must be such as to bear that universal re- 
lation to each other, which we have fully explained in the other 
instruments. It is not difficult to make all the necessary ad- 
justments properly, although it may not appear quite so handy 
to correct its errors as in the case of the Y- level. Once ad- 
justed, however, the instrument will remain so for a long time, 
and it will give the operator considerable satisfaction, if used 
with the ordinary care. 

The adjustments of the level, and the telescope for collima- 
tion, will now be briefly mentioned. 

Put on the sun-shade, and focus the eye-piece until the 
hairs are distinctly visible and the parallax destroyed; then 
proceed as follows: 

Operation. — Turn the instrument so that the telescope shall 
stand directly over the line of two opposing leveling screws. 



THE A. LIETZ COMPANY. 65 

and draw the bubble to the middle of the tube by means of the 
foot-screws. Then turn the instrument on its center 180 de- 
grees, and if the bubble remain centered the adjustment is 
perfect. Any displacement, however, will have to be corrected 
by taking up one-half of it with the capstan-headed screws at- 
tached to the level case, and the other half by the foot-screws. 
This operation must be repeated several times, in directions 
normal to each other — that is, over one set of opposing foot- 
screws as well as over the other, until the telescope may be 
swung in any position and the bubble will remain in the mid- 
dle. See that the adjusting screws of the level vial are firm, yet 
avoid all unnecessary force in tightening them; all cramming 
is injurious, and tends to destroy the proper degree of refine- 
ment required. 

After having set the diaphragm so that the cross-hairs shall 
be absolutely horizontal and vertical, which is easily done by 
loosening the capstan -headed screws and turning the diaphragm 
slightly, being guided by some point bisected by the horizontal 
hair, we now proceed to adjust the cross-hair, which must be 
brought into the collimation line. Several methods are known; 
the one which is always available, however, is that by means of 
stakes and level-readings upon them, and it is to this that we 
shall confine ourselves here. 

Operation. — Choose a piece of ground nearly level, set up 
the instrument and center the bubble. Drive a stake (point 1) 
firmly, say two hundred or three hundred feet from the instru- 
ment, in any convenient direction therefrom. Hold the level 
rod upon it and take a reading. Now point the telescope in the 
opposite direction, the bubble being centered, and plant another 
stake (point 2) at the same distance from the dumpy, driving it 
until the rod shall read the same as upon the first point. These 
two stakes are on the same level. Now set up the instrument 
about ten or fifteen feet from the first stake, and bring the 
bubble to the center; take a rod-reading on point 1, and then 
on point 2. If the two readings are alike with a truly centered 
bubble, the hair is collimated. If there is any difference, take 
up nearly all of it, by moving the diaphragm with the cross- 
hairs either up or down, as already explained. Repeat this 



66 MODERN SURVEYING INSTRUMENTS, 

operation until the readings on points 1 and 2 are identical, 
when the instrument is in adjustment. 

The vertical hair is of no particular importance. 

With these precautions, a dumpy level may he made abso- 
lutely accurate, and there is no reason why, for any of the land 
surveyors, and for nearly all of the engineer's work, this com- 
pact and steady instrument should not meet every requirement. 
We frequently discuss its merits with our customers, and have 
never hesitated to recommend it. 

Test of Telescopes in General. 

Adopted from our old catalogue. 

If a telescope is to be tested for its qualities, make sure 
that all its lenses are perfectly clean. 

To test for definition, use small, clear print, and view it 
from a distance of from thirty to fifty feet. If the print ap- 
pears clear and well defined, and fully as legible at this distance 
as if viewed with the naked eye at the distance of distinct 
vision, the surfaces of the object-glass are perfect and well fin- 
ished. If, on the contrary, the print appears dull and indis- 
tinct, and the finer details illegible, or even invisible, the 
surfaces are imperfect and faulty, for the rays proceeding from 
the various points of the object are not refracted to their cor- 
responding points in the image. 

Indistinctness may be caused by spherical aberration. 

To test this, cover the object-glass with a ring of black 
paper, reducing the aperture to one-half; again focus small 
print to distinct vision; remove the ring of black paper and 
cover the center of the object-glass (previously left open), then 
mark how much the object-glass has to be moved in or out for 
distinct vision. If the spherical aberration has been reduced 
to a minimum, very little, if any. slide motion is necessary to 
obtain a distinct view under both tests. The amount of move- 
ment, however, constitutes a measure for the spherical aberra- 
tion of the object-glass. 

Another test, but not as good as the one just mentioned, is 
to focus an object to distinct vision; then slide the object-glass 
in or out, observing at the same time the quantity of motion 



THE A. LIETZ COMPANY, 67 

necessary to render the object indistinct. If the spherical ab- 
erration is completely corrected, the object should, theoretically, 
be rendered indistinct by the slightest motion of the lens; but, 
practically, this is not the case, as the eye will accommodate itself 
in a measure to the difference of divergence of the rays, caused 
by the motion, in or out, of the object-glass, in the same manner 
as it will accommodate itself to near and distinct objects when 
viewing without the aid of lenses. So, if the image formed by a 
perfect object-glass is viewed by another perfect lens of long 
focal length, say six inches, the object-glass might be moved in 
or out one-fourth of an inch from the point of distinct vision, 
and the object will still appear comparatively clear, as the one- 
fourth-inch motion, with an eye-lens of such long focal length, 
cannot cause enough difference in the divergence of the rays to 
prevent the accommodation of most eyes to it. The shorter the 
focal length of the eye-lens, the more rapid will be the change 
of divergence or convergence of the rays with a certain amount 
of motion; therefore, the second test is only applicable with 
eye-pieces of very high power, which, at the slightest motion 
in or out, will cause a sufficient amount of divergence of the 
rays to prevent the accommodation of the eye to the change. 

To test the chromatic aberration, either a celestial body or 
a white disc should be selected for an object. 

Focus the object to distinct vision, thereupon move the 
object-glass slowly in and out alternately. If, in the first 
instance, a light yellow ring is seen at the edge of the object, 
and in the second one a ring of purple light, the object-glass 
may be considered perfect, as it proves that the most intense 
colors of the prismatic spectrum (orange and blue) are corrected. 

To test the flatness of field, take a square, flat object, the 
sides of which are about four inches long and perfectly straight 
— the best object is a heavily-lined square, drawn on white 
paper with india ink. Sight this object from such a distance 
that it will nearly fill the field of view of the telescope, and see 
if it still appears flat and its sides perfectly straight; if so, the 
telescope is a good one. If, on the contrary, the object appears 
distorted, i. e., if the sides, instead of being straight, form 
curves and the surfaces appear concave, instead of flat, the tel- 



68 MODERN SURVEYING INSTRUMENTS, 

escope is not good, for it shows that the proportions of foci, 
aperture and distances between the different lenses are not ac- 
cording to the laws of optics; owing, generally, to the attempt 
to force the magnifying power beyond its limits. 

As all the refractions of light in the telescope are caused by 
flat and spherical surfaces, it is evident that the edge of a round 
flat object, when used for the above test, cannot be distorted, 
but that the surface only will appear concave to a keen observ- 
ing eye. A telescope which distorts the image to a perceptible 
degree, will not, however, cause any errors in common use, if 
only one point in the lens is taken in all observations, but it is 
decidedly objectionable in stadia measurements, where two 
points in the field of view are used at the same time. 

To Find the Magnifying Power of a Telescope. 

A practical method for finding the magnifying power, 
available to anyone, which does not require any apparatus, 
taking up only a few moments time, is the following: 

Set up the instrument, and about twenty or thirty feet 
therefrom hold up a graduated rod. Observe the rod with one 
eye by direct vision, and with the other through the telescope. 
Assume a certain space on the rod, say the height of a numeral, 
or two sharply-drawn lines, and count the number of divisions 
on the rod in that space: then observe the number of divisions 
that are seen by the naked eye in the same space enlarged. 
The ratio between the two is the power sought. It is the read- 
ing of a magnified space of known length on the graduated face 
of the rod. With a little practice both eyes will be able to dis- 
tinguish the rod divisions at the same time. If what is known 
to be 0.1 of a foot, is enlarged by viewing it through a telescope 
so as to cover the space of 2.4 feet as seen by the unaided eye, 
the magnifying power is 24 for the distance in focus. The 
real power is somewhat less, for as the tube of the telescope is 
drawn out for near objects, the power necessarily increases. 
The magnifying power obtained by this method holds good for 
the distance that the rod can be read by the unaided eye, and 
it is always somewhat greater than the actual power. 

It is well for the engineer to make a test of the power of a 



THE A. LIETZ COMPANY. 69 

telescope himself, for it is to the interest of the maker to rate 
this higher than it really is, for very obvious reasons. This 
method suggests itself as perfectly practicable, and is readily 
tried at the time of purchase. 

For a very accurate determination of the magnifying power, 
it is necessary to ascertain the focal length of the objective and 
that of the eye-piece, in order to compare them and to find their 
proportion. While the former is easily obtained by a direct 
measurement from the objective lens to the cross-hairs, the lat- 
ter, usually containing an entire system of lenses, presents 
numerous difficulties. For this purpose we possess an apparatus, 
which was especially designed and built for us by a prominent 
optician in Germany, and which is so perfectly adjusted to do 
its work, that we think it of interest to explain it in a general 
way. 

Referring to the accompanying illustration: 

Upon an iron base F stands the pillar E, carrying the 
wooden bar D, upon which three standards are mounted. At 
one end of the bar the microscope A is held by a fixed stand. 
Its tube is adjustable to focus by the screw a. At the other end 
is the collimator B, which slides upon the bar and is held by 
the screw d. Between the two is the holder for the eye-piece C 
under consideration. The pillar slides upon the bar, and is 
clamped by the screw c. The screw b raises or lowers the small 
platform on which the eye-piece rests. The whole is recognized 
fully in the drawing. 

To determine the focal length of any lens or combination, 
the eye-piece, etc., is placed on the platform as shown, the col- 
limator being turned with its small opening e towards the light. 
(It may be used in the daytime, or by lamp-light at night.) 
The whole is properly adjusted by sliding the collimator and 
the platform on the bar as required. The eye-piece, which 
has been carefully aligned between collimator and microscope, 
is then viewed by the latter, which is focused by the screw a, 
until the collimator opening e is clearly and distinctly visible as 
a round disc of light with a sharply-defined outline. In the 
field of the microscope a small graduated scale is seen, and by 
this scale the diameter of the light disc may be measured, by 



70 MODERN SURVEYING INSTRUMENTS, 

simply counting the' number of lines that it covers. These 
give the focal length of the eye-piece directly in millimeters, 
and that with absolute accuracy. 

Dividing the focal length of the objective (when the tele- 
scope is focused to mean distance) in millimeters, by the value 
just obtained, gives the magnifying power of the telescope under 
consideration. 

This apparatus measures focal lengths up to 80 centimeters 
(31i inches). It is applicable to simple lenses, as well as to any 
combination of them. Even concave lenses may be determined 
by it, but in that case the image lies behind the lens, and the 
device will measure until the lens touches the microscope, and 
no further. 

This is the only apparatus of the kind anywhere, as it 
was especially designed for us, and built for the exclusive use of 
the Company. 

If any of our customers want the focal length of an eye- 
piece determined, we shall cheerfully do so, without charge, 
upon receipt of it, which should be sent carefully packed by 
express. 

Adjustments of the Plane Table Alidade. 

Without going again into all the details of instrumental 
adjustments, it behooves us to enumerate the points required of 
this instrument when in proper condition. These are: 

1st — That the fiducial edge of the rule be absolutely straight; 

2d — That all parallax be destroyed, by placing the cross- 
hairs in proper focus; 

3d — That the line of collimation move in a vertical plane; 

4th — That this plane be normal to the plane of the ruler; 

5th — That the same plane also intersect the fiducial edge 
of the ruler, or at least be parallel thereto; 

6th — That during parallelism of the optical axis and the 
fiducial edge, the zeros of the vertical arc and its vernier cor- 
respond. 

This instrument is used in the topographical departments 
of the U. S. Coast and Geodetic Survey, and the U. S. Geological 



THE A. LIETZ COMPANY. 71 

Survey, and is exclusively applied in mapping the topograph- 
ical features of the country in Europe, usually by officers of the 
army, who control these surveys, after the triangulation points 
have been established. 

This method of surveying has been constantly improved 
in practice, particularly by the experts of the Geological Survey, 
and it may be safely said that, with the required accuracy, 
nothing surpasses it for small-scaled work in speed and applica- 
tion. All the bulky parts of the table have been reduced to a 
minimum, so that it may be handled with comparative ease in 
the roughest mountain country. 

We refer our readers to appendix No. 22 of the Coast Survey 
Report of 1865, which may be had separately in bound book 
form, called The Plane-Table and its Uses, as an excellent theo- 
retical and practical treatise of this interesting subject. 



i 



PART III. 



PROFESSIONAL PAPERS 



PUBLISHED BY 



THE A. LIETZ COMPANY, 

SAN FRANCISCO. 



189 3 






NO. 1. 

A SHORT AND PRACTICAL TREATISE 

ON 

Stadia Surveying- 

OR 

TACHYMKTRY, 



TABLES 
For the Determination of Horizontal Distance and Elevation. 



Written for this Manual by 
OTTO VON GELDERN. 



The value of this method of obtaining distances is now so generally appreciated, 
that every engineer will use it in his work, wherever the accuracy obtainable is suf- 
ficient for his purpose. While it cannot replace the usual means of precise linear 
measurements employed in cadastral surveys, it offers many other advantages that 
cannot be too highly estimated. Under difficult topographical conditions the results, 
if carefully obtained, may be even better than those of the ordinary chain. At all 
events, the rapidity with which distances may be measured at all times, and its 
adaptability to inaccessible places, have given it that prominence in topographical 
work which it justly deserves. 

To make quick and reliable observations of this character, the instrument used 
should be a good one, and its telescope, above everything else, must possess power, 
definition and light in a high degree, in order to enable the observer to read the so- 
called telemeter rod with precision on long sights. 

The Principle of the Stadia Method. 

The fundamental basis underlying this method of measuring is well known, and 
is simply the geometrical proposition that parallel lines subtending the same angle 
from a given point, are proportional in length to their distances from that point. 
This explains generally the applied principle governing the stadia; all the modifica- 
tions of it are due to the structure of the instrument used, and to certain optical 
and geometrical principles that involve corrections to be introduced under certain 
conditions of sight. 

By placing two additional horizontal threads in the telescope, at equal distances 
from the middle hair, we obtain a gauge that may be applied to a graduated rod, 
the intercepted space upon the rod increasing, as the distance between it and the 
telescope increases. If the graduation to some adopted unit of measure be so 
marked, that it may be read clearly and distinctly without error on longer distances, 
it is evident that a mere inspection of the rod by means of the telescope, will be 
sufficient to indicate its distance from the instrument. 

The threads may be inserted at random, and the rod marked to correspond to 
known distances; or they may be placed so as to intercept one unit of measure on 
the rod to a given number of units in distance. The latter is that generally em- 
ployed, and the usual ratio is 1 in 100. 



THE A. LIETZ COMPANY. /5 

When the distance measured between two points is at an angle with the horizon, 
it becomes possible to determine the co-ordinates of horizontal distance and differ- 
ence in elevation of the triangle, provided the angle of the slope is known. This 
may be read on the vertical arc of the instrument. If, in such cases, the telemeter 
rod be held at right-angles to the line of sight, the horizontal distance will equal 
the cosine of the observed vertical angle, multiplied by the distance indicated by 
the rod. This must be corrected by certain small values, to which reference will be 
made further on. And similarly does the sine of the angle indicate the difference 
in elevation. 

The usual custom here is to hold the rod vertical under all conditions, which is 
more readily accomplished, and, in certain localities, perhaps the only possible way 
of holding it. 

Optical Features and the Constants c and k. 

Certain optical principles do not admit of a stadia measurement from the point 
occupied by the center of the instrument, but from a point outside of the objective 
lens, equal in distance to its focal length. This gives rise to a certain value by 
which the stadia distance must be increased, and which may be practically a constant 
for any length. It may be determined with sufficient accuracy by adding two meas- 
urements, taken with an ordinary scale or tape, from the object glass of the tele- 
scope, when the latter is focused to a distant object: one to the capstan-headed 
screws, holding the diaphragm with the cross-hairs, and the other to the center of 
the axis. The sum of these two (/4- h, figure 1) is the constant c, which must be 
added to every horizontal distance, irrespective whether long or short. 




In figure 1, let a =any rod reading, K == a constant expressed by the relation 
of the distance between the stadia threads and the focal distance of the object glass, 
then K a — d = distance from the focal point to the rod, for 

s : f : : a : d , or 

(1) d = ^J— , wherein J— represents the constant K. 

s s 

It must be mentioned, however, that this is not strictly correct, because the 
focus is changed with the distance of the object, and the value / therefore variable. 
Nevertheless, the results, unless obtained on very short ranges, are as close as re- 
quired for the purpose of the stadia, by assuming J— as a constant of any value 

s 
that we may choose to assign it when we place the hairs, the ratio 1 : 100 being 
usually adopted. 

To express the distance D of the rod from the point occupied by the instru- 
ment, on a level surface, we have, therefore, 

(2) D == K a + c , 



76 MODERN SURVEYING INSTRUMENTS, 

remembering c as the constant expressing the distance from the center of the in- 
strument to the outer focus of the objective, which must be added in every case. 

If A', as customary, equal 100 and c = 1.15' (as in the ordinary large transit), 
then I) = 100 a + 1.15', so that the following rod readings would correspond to the 
distances as shown: 

1 foot = 100 fl - + 1.15 ft = 101.15 feet. 

1.69 feet = 169 ft - + 1:15 ft - = 170.15 " 

2.33 " = 233 ft + 1.15 ft = 234.15 " 

1 meter- 100 "'• + 1.15 ft = 100.35 meters, 
and so on. 

Reduction of Elevated or Depressed Sights. 

If, now, the observation be made on a slope with rod held vertically, the angle of 
elevation or depression may be expressed by n, and the angle intercepted between 
the stadia hairs by 2 m. 

Any rod reading a may then be reduced to the reading a Y , or normal rod read- 
ing, by the following formula, which is obtained from the elements given in the 
diagram, figure 2: 

(3) 



cos n + \ sm >l [ tan (n -\- m) -\- tan (n — m) ] 
Now, since the angle m in an instrument rated 1 : 100 only amounts to 17 
minutes, it is evident that the expression 

\ sin n [ tan (n -\- m) -\- tan (n — m) J 
is almost the same as sin n tan n, the difference being so small that it will not be 
noticeable at all in any of the stadia requirements, and writing sin n tan v in terms 

of the cosine, we have , and substituting in formula (3), it will reduce 

cos v 
to the simple expression 

(4) a x = a cos n. 

This, then, is the normal rod reading, which, by applying the constant K, gives 
the distance K a cos n , representing the hypothenuse h of a right-angled triangle, 
of which the horizontal distance d and the difference in elevation e are the co-ordi- 
nates. Their values in turn are proportional to the cosine and sine of the angle n, 
so that the distance 

(5) d = K a cos - n . 

and the elevation e = K a cos n sin n , which is 

(6) ' A a I sin 2 n . 

(It is understood, in the case of the difference in elevation between the two 
points (e), that the middle hair touches the rod at a mark corresponding to the 
height of the instrument, as shown in figure 2.) 

Introducing, now, our constant c , which causes corrections also dependent 
upon the angle n , we must add to the horizontal distance d the value c cos n ; and 
to the elevation e the value c sin n , so that the corrected horizontal distance is 

(7) I) <■ cos n 4- & ° cos 2 n , and the corrected elevation 

(8) E - <■ sin a 4- K a h sin 2 n ; 
or, if the constant K = 100 . 

and the constant c = 1.15 , 

then J) - . 1.15 cos n -\- 100 a cos-' //. , 
and K 1.15 sin n -\- 100" I sin 2 »■ . 



THE A. LIETZ COMPANY. / ( 

If, for example, the rod reading a be 2.22 feet, and the vertical angle n = 20", 
then 

D = (1.15 X cos 20° = 1.08) -f ( 222 X cos-' 20° =196.03) = 197.11 ft. 

E = (1.15 X sin 20° = 0.40) -f [222 X Sm 4 °° = = 71.35 "j = 71.75 ft. 

The second member of the equation is the important one, and that which char- 
acterizes the formula, the first being small and a constant for the same angle, inde- 
pendent of the distance. But as it cannot well be neglected altogether, it is 
customary — since it is not readily incorporated in tabular values — to supplement 
a table that shall furnish the values of d and e for different angles of inclination, 
by the terms c cos n and c sin n in a special place, usually at the bottom, where 
they may be readily found and applied. They vary so little from degree to degree 
that for the ordinary stadia measurements they may be entirely neglected. 

The annexed tables were calculated by the formula- 

d — K a cos - n 
e = K a \ sin 2 n , 
and so arranged as to give the distance d and the elevation e for every 2 minutes of 
arc for a value of K a = 100, the rod held vertically. They admit of a simple appli- 
cation. 

By what has preceded, let it be required to find the horizontal distance and the 
difference in elevation, when the rod indicated 285 feet and the vertical arc 10° 12'. 
Look for the column headed 10°; run down this column with your finger to the 
figure on the same line with number 12 in the left-hand or minute column, where, 
for 100 feet, d is found as 96.86, and e 17.43. Multiply both of these by 2.85. This 
reduces the distance 285 feet to d — 276.05', and e = 49.67'. At the bottom of the 
page will be found values of the corrections due to c for different focal lengths. 
Three values obtain: 1.90 (the large Y- level), 1.15 (the large transit), and 0.75 (the 
small transit). If a large transit has been used we look for the corrections corre- 
sponding to c=1.15, and in the case before us we would obtain 1.13 and 0.21. 
These are added to the values already obtained, and we have: 

corrected horizontal distance D = 277.18 feet, 
and corrected difference in level E ■=. 49.88 feet. 

The Stadia Board or Telemeter Rod. 

For stadia work an ordinary leveling rod may be used, and, with the aid of a 
pocket level (a so-called rod level with a circular bubble, that may be fitted and held 
to the edge of the rod), its vertical position may be assured. By employing two 
targets and reading them with care, the results will be as precise as the telescopic 
power admits. It is usual, however, in order to save time, to prepare a self-reading 
rod, so marked that it shall facilitate rapid observation and reduce all chances of 
error from a wrong reading. Many patterns are employed by a combination of geo- 
metrical figures and by different colors (red, black, white), that are intended to 
indicate at a glance the space between the upper and lower hair in terms of the rod 
measure. These patterns are either painted directly on a board from 10 to 12 feet 
long, that may be folded for convenience in transportation by a hinge in the middle, 
or on stiff canvas, in which case it may be rolled up for carrying in the pocket, and 
tacked to a suitable board whenever required. These so-called flexible stadia boards 
answer very well, but the former are to be preferred in aceuiate work, as they can- 
not be materially distorted by conditions of weather. 



78 MODERN SURVEYING INSTRUMENTS, 

In case the stadia hairs were set arbitrarily, it becomes a simple matter to ascer- 
tain the constant K. A distance of eight hundred feet or more is laid off on a level 
surface with a steel chain, and marked at each hundred feet. The instrument is 
placed the distance of its constant c away from one of the end points, and readings 
are taken on a leveling rod at every hundred-foot mark. From these the ratio between 
distance and rod reading is readily determined . 

Or, a stadia board may be so divided that a unit of its measure shall agree with 
a hundred-foot space. If a blank board be held at every hundred-foot mark on the 
ground, we may draw upon it the intersection of the upper and lower hair for each 
station. If the rod units so obtained vary slightly from each other, the mean of 
them may be adopted without appreciable error, which is subsequently divided into 
smaller spaces, to read as close as desirable. In this wise we obtain a rod corre- 
sponding with the instrument of which it then becomes a part. 

Some instruments possess adjustable stadia wires. In that event the hairs may 
be set to suit the rod. 

In all these cases it is evident that the constant c must be previously determined 
and properly applied. 

General Remarks. 

In making a stadia observation, after having set up and adjusted the transit over 
a point, direct the telescope to the rod and clamp the instrument in position. Move 
the telescope in a vertical plane, until the middle hair of the three intersects a line 
on the rod as high above the ground as the telescope axis is over the point occupied, 
and read the space intercepted betweeu the upper and lower hair. Au even foot- 
mark, or unit-mark, can always be found, upon which either the upper or lower 
hair may be placed, that will satisfy the conditions nearly under which a should be 
taken, and from it the rod may be read quickly up or down. To obtain the vertical 
angle, the telescope should then be moved either up or down with its tangent 
screw, to the exact intersection on the rod corresponding to the height of the in- 
strument — which is 4.5' ordinarily — and the vertical arc read. 

There are occasions when the middle hair cannot be placed on the rod as ex- 
plained — in the woods, for instance, when parts of the rod may be covered by 
leaves — and in that event we may read it wherever its exposed space permits, and 
make the necessary corrections afterwards. It is one of the particular advantages 
of the stadia that it may be used under very unfavorable conditions of the field, in 
forests, swamps, along declivities, etc., and yet obtain very reliable results. As 
long as the rodmau is able to get to a place and to hold up his rod, and the observer 
can see a clear space on the face of it, the reading may be obtained that shall lead 
to the determination of the horizontal distance and to the difference in elevation. 

In cases where both stadia wires are not visible on the rod, the space between 
the middle hair and the visible one may be read off and multiplied by 2, it being 
presumed that the upper and lower are equi-distant from the middle hair. But 
where very large vertical angles accompany the sight, however, it is not well to rely 
absolutely upon the result, for it is quite readily demonstrated that the horizontal 
distance will be either too large or too small by a quantity, that, in a rod-reading of 
.">. doubled to 10 feet, for instance, with a constant K = 100, an angle n = 40°, will 
come within about fef, of the correct value. With a vertical angle of 20 c under the 
same conditions, the error in distance is about fo$. In the former case the correc- 
tion would be plus or minus 2.43, and in the latter plus or minus 1.59 feet. But it 
shows that even under the most unfavorable conditions of sight we are able to 
approach the true distance within all the requirements of topographical surveying. 



THE A. LIETZ COMPANY. 79 

A survey may be made with the stadia altogether, or it ma,j be preceded by a 
triangulation, in order to locate a number of fixed points — the relative elevations 
of which are established with a leveling instrument — between which the topography 
is filled in with the stadia. The latter method is necessarily more trustworthy, and 
should always be adopted where large areas are to be surveyed; but if the engineer 
is pushed for time, he may omit the triangulation and yet obtain very good 
results. In such an event great care should be exercised in locating the turning 
points. Occupying point 1 and observing upon point 2, read carefully the azimuth 
on the plate, and check it by recording the bearing of the needle also. Kead your 
distance from the rod and record that. Having placed the middle horizontal hair 
on the rod as high above its foot as the telescope axis is over point 1, observe the 
vertical angle, which is either plus or minus, and note it down. Leaving point 1 
and proceeding to point 2, set the instrument over the latter and level up. It may 
be clamped upon any desired known azimuth, but the reading of the plate should not 
be omitted in a direction toward point 1 . Kecord this with the bearing of the needle, 
which will give the reverse course of the sight 1 to 2. Observe again the distance 
between the points as shown by the rod, and note it down, as well as the vertical 
angle from 2 to 1, as explained, which should give the same result as before with re- 
versed sign. These precautions of observing twice between turning points form a 
very valuable check, and should never be omitted where every other datum is lack- 
ing and the stadia method alone is relied upon. After having taken his back-sights, 
the surveyor proceeds with the observation of all intermediate points required for 
his topographical details, before locating point 3 for a further advance. 

Work may be done still more rapidly by occupying every other point only; but 
in that case the bearings of the lines are solely obtained by the needle, and there is 
no check. 

By employing two or even three rodmen, distributed about the field as ad- 
vantageously as possible, the engineer is able to observe rapidly without loss of 
time. It is always well to have a recorder accompany the party, whose sole duty it 
becomes to note down the observations of points, and the description as to what 
these points represent. If necessary and desirable, a small drawing-board may be 
taken into the field, and, instead of a recorder, a plotter may be employed, who lays 
down the reduced observations as the work progresses. This is considerably slower, 
but it offers the advantage of a completed field map when the survey is finished. 

Instead of employing the tables here given, the reductions may be quite expedi- 
tiously and accurately made in the field by means of the logarithmic slide scale, which 
the author employs in his surveys altogether, a description of which is readily 
obtained. 

With a little practice the engineer will work himself into the use of the stadia, 
and become an expert. Tachymetry, as it is called, is an indispensable method of 
measuring, and one that the surveyor of to-day must acquire. 

Considerable might be said regarding useful hints and instructions for the field, 
but we prefer to let every engineer find his own method in the practical application, 
knowing well that after he has mastered the principle, he will adopt a system of 
work best suited to his requirements. 

The essential requisites for a successful operation are a good clear telescope, 
affording a distinct view of the rod on long ranges (the author prefers the inverting 
eye-piece, as one affording better light and a more distinct image, there being no 
particular advantage in seeing objects erect, as the mind soon accustoms itself 
readily to an inverted vision), a steady instrument, and, for the method under dis- 
cussion, a true vertical rod . 

/ 



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99.72 5 
99.71 5 
99.71 5 
99.70 5 
99.69 5 

99.69 5 
99.68 5 
99.68 5 
99.67 5 
99.66 5 

99.66 5 
99.65 5 
99.64 5 
99.63 6 
99.63 6 

99.62 6 
99.62 6 
99.61 6 
99.60 6 
99.59 6 

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88 3.49 
87 3.55 
87 3.60 
87 3.66 
86 3.72 
86 3.78 

85 3.84 
85 3.90 
84 3.95 
84 4.01 
83 4.07 

83 4.13 
82 4.18 
82 4.24 
81 4.30 
81 4.36 

80 4.42 
80 4.48 
79 4.53 
79 4 59 
78 4.65 

78 4.71 
77 4.76 
77 4.82 
76 4.88 
76 4.94 

75 4.99 
74 5.05 
74 5.11 
73 5.17 
73 5.23 


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97 1.74 
97 1.80 
97 1.86 
96 1.92 
96 1.98 
96 2.04 

96 2.09 
95 2.15 
95 2.21 
95 2.27 
95 2.33 

94 2.38 
94 2.44 
94 2.50 
93 2.56 
93 2.62 

93 2.67 
93 2.73 
92 2.79 
92 2.85 
92 2.91 

91 2.97 
91 3.02 
90 3.08 
90 3.14 
90 3.20 

89 3.26 
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No. 2 



REMARKS 



Principle of the Logarithmic Slide Scale 

Written in 1885, but entirely revised for this Manual in 1893. 



HUBERT VlSCHER. C. E. 



The employment of mechanical devices for performing computations has at- 
tracted the attention of arithmeticians for a couple of centuries past, and to no class 
of persons is it of more direct interest than to those engaged in technical callings. 
These endeavors have been pursued upon several distinct lines, and we may notice 
by way of classification: 

1st. The endeavor to perform desired arithmetical operations by devices dis- 
tinctly mechanical in their nature, seeking by skilful combination of mechanical 
elements to carry out the ordinary sequence followed by the computer in making 
the calculation. We may here mention the celebrated machine of Babbage; and as 
a more recent illustration, the "Arithmometer" of Thomas, an instrument of only 
moderate cost, and one coming constantly into greater use. 

2d. The use of geometrical figures representing the mathematical relations ex- 
isting between mutually dependent quantities. This method, first suggested by the 
development of the Des Cartian geometry, has, in very recent times, been developed 
into a new science, graphostatics — which does not merely seek to present the de- 
ductions of analytical reasoning graphically, but starting at the elements, builds up 
methods of its own in which the arithmetical conceptions of magnitudes fall more 
and more into the back ground and are replaced by operations which are mechanical 
in application, if not in their conception. 

Besides these two methods, we have another, somewhat partaking in nature of 
both, yet embodying a distinct principle of its own, that of the Logarithmic Slide 
Scale. 

It is here proposed to take a cursory survey of this Held, which is of wide ap- 
plication and certainly of interest, being an important agent for the saving of time- 
robbing computations. It is worthy of more general attention than it has received 
in this country; though in Europe, the slide-rule is recognized as the engineer's 
daily pocket companion. 

The slide-rule rests upon two most simple principles: first, that magnitudes in 
general may be represented by the length of lines; second, that these lines, when 
measured off upon one another may represent by the length of a resulting line, 
either a summation or a difference of the magnitude which the lines represent. The 



THE A. LIETZ COMPANY. 00 

first principle is made use of in the logarithmic graduation of the scales; the second 
principle finds application in the sliding motion which we impart to the scales. 
Slide-rules have been constructed of many kinds and for many special purposes, 
but they will all be found to reduce to these two elementary principles. 

The use of the logarithmic graduation here, as in all other cases where logar- 
ithms are employed, is due to the desire to reduce arithmetical calculations by one 
step in the scale of operations; thus replacing multiplication and division by addi- 
tion and subtraction, and reducing involution and evolution to multiplication and 
division. 

The method in which the logarithmic graduation is carried out is explained 
most easily by taking a special case, and we refer to the scale AB A' ' B' on Fig. 1. 
The length of this scale, measured between the two extreme outer limits, marked 1, 
1. is assumed as a unit of length; and what the absolute length of this unit is, is 
perfectly immaterial. We may, for purposes of illustration, assume it to be just one 
foot long. As a preliminary step, let us first imagine this length divided off into say 
1,000 equal parts. Before proceeding further, however, let us recall to mind the well 
known property of "periodical repetition" peculiar to the Briggs' system, whereby 
all numbers represented by the same numerals, grouped in the same order, are repre- 
sented by the same logarithm, independent of the characteristic or mantissa. 

It is clear that with the aid of a table of logarithms and using our scale of equal 
divisions, we may at once assign to any logarithm in the table a place on the scale, 
such that its distance from the zero (or left-hand end of the scale) may correctly 
represent the value of the logarithm, plotted in our unit or standard of length. Do- 
ing this for all logarithms, commencing at the number 1, and progressing by any 
suitable interval (say 1-100 of unity), let us mark each so determined point by a cross- 
line on the scale, and (in order to preserve it for future use) mark opposite the 
cross-line the number corresponding to the logarithm which the cross-line fixes. 

Having done this, we reach the right-hand end of our scale, when in our table 
we reach the number 10. It is apparent that our scale represents graphically a table 
of logarithms for all whole numbers between 1 and 10, with suitable subdivisions, 
and corresponds in all particulars to the printed table from which it was constructed. 
But it is equally clear that if we agree to consider the scale as representing the frac- 
tional part of the logarithm only, and without reference to the " characteristic," we 
may at once extend its range so as to embrace the whole field of positive numbers 
without any reservation. The "characteristic " of the logarithm, however, only de- 
termines the position of the decimal point in its number. Therefore, this stipula- 
tion about dropping the characteristic implies, conversely, that our scale shall only 
give us the numerals which express a number, without reference to a decimal point; 
so that, if we read 2, 3, 5 on the scale, we may read this as 235, or as 235 with any 
number of zeros affixed or prefixed to it; as 0.00235 or as 2350, for example. In 
slide-rule calculations there must always be some foreign means employed for cor- 
rectly assigning the position of the decimal point, a matter which will be referred to 
again later on. 

It is now practically shown what constitutes the construction of the logarithmic 
scale — only one, however, of an infinite variety of possible logarithmic scales. Any 
series or group of numbers may be made the basis of a similar scale. Thus, by means 
of their logarithms, we may construct logarithmic scales for the natural sines or 
tangents of angles (see scales E and F, Fig. 2), or for any other function of angles; 
or, as the choice of the length of our unit was left perfectly open, we may plot scales 
to any enlarged or reduced scale, which latter observation is important, as it forms 



86 MODERN SURVEYING INSTRUMENTS. 

the basis of all operations embodying involution and evolution in the slide-scale 
calculations (as will at once appear clear by remembering that these operations, log- 
arithmically speaking, imply multiplication and division). 

Returning, however, to our constructed scale, Fig. 1, let us conceive it severed 
longitudinally along its central line by a cut, a b, so as to fall into two identical 
scales, AA' and BB\ Furthermore, let us regard these scales as free to slide later- 
ally to the right or the left, along their common line of contact, a b. With this mo- 
tion we at once obtain the means of performing any desired multiplication or division 
This is clear, if we consider that the divisions upon our scale are magnitudes logar- 
ithmically plotted, and that, therefore, an addition or subtraction, as far as these 
are concerned, executes a multiplication or division as regards their numbers (which 
are, by-the-by, the only records on the scale). With this capacity of motion, we 
have attained the simplest form of the slide-rule. A single setting of the slide per- 
forms a multiplication or division; if desired, a combination of both, i. e., a propor- 
tion; and in many cases not simply for a single set of numbers, but for a whole 
series of sets of numbers at one and the same operation. The details of manipula- 
tion are not entered into here, having only the principles of the slide-rule in view. 
If desired, these can all be found described at length in the printed directions fur- 
nished with the scales. Be it remarked, however, that although the whole operation 
has been essentially a logarithmic one, we lose sight entirely of logarithms having 
been used at all. This is always the case in operations with the slide-rule. In fact, 
the peculiar merits of the slide-rule can hardly be better expressed than by pointing 
out this unconscious gaining of all the advantages of using logarithms, while saved 
the labor of taking them from tables. While the whole conception of the slide-rule 
is logarithmic in its nature, save as a means of understanding its construction and 
in studying out particular modes of application to meet special cases, this is lost 
sight of entirely in its use. 

The slide-rule, as constructed by the firm of Dennert & Pape (in Altona, Ger- 
many), is shown in figures 1 and 2; the latter being an isometrical view of the scale 
in order to better show its working parts. These are as follows: A thin slab of box- 
wood, called the "slide," upon the edges of which two scales, B and C are engraved. 
The slide being fitted with tongue-and-grooved edges at its sides, is free to move be- 
tween two other boxwood surfaces also bearing scales, A and D. The latter are 
parts of the same piece of wood, being connected with each other underneath the 
slide, and both of these (together with the connecting boxwood member) form the 
"rule, "into which the slide is recessed laterally while left perfect freedom of motion 
lengthwise, in both directions. Scales A and B, as has been shown, are exact dupli- 
cates of one another, as are also scales C and D, thus forming two pair of scales. 
The latter pair, in principle of graduation correspond to the former pair entirely, 
but are graduated to one-half the scale (or length of unit) of A and B. This reduc- 
tion in scale would make each of the upper scales one-half the length of the lower 
pair, were it not that we utilize the remaining half by engraving thereon another 
duplicate set of the smaller scales, placed alongside of the former; thus making the 
total length of the upper double pair exactly that of the single lower pair. Each half 
of either " double scale " is not to be regarded as separate from its neighbor, but as 
joined to it, so as to form one continuous scale; the idea being to allow the double 
scales to represent all numbers for an interval of two whole powers of 10, while the 
lower scales represent all numbers for half that interval; if the lower scale embraces, 
for instance, the period from 1 to 10, then the upper similarly represents the period 
from 1 to 10 on the first (or left hand) halves, while the second (right hand) halves 



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thp: a. lietz company. 87 

simultaneously represent the numbers from 10 to 100. The pair of scales on the 
slide (though movable as a pair) stand permanently with their extreme ends directly 
over and under one another; so also stand permanently fixed opposite one another 
the ends of scales A and D. 

Now, while the double scales C and D, on account of their lateral motion along 
their common line of contact, answer the same purposes exactly that the lower pair 
do (that is, perform multiplication and division also), a little reflection and study 
of the figure will show how, regarding A and D or B and C as pairs, the following 
must always hold good, on account of the peculiarities of the mode of graduation: 
any number on the upper scale stands directly over its root on the corresponding 
lower scale; and conversely, any number on a lower scale may be raised to the sec- 
ond power by taking the corresponding number exactly above it in its companion 
scale. Thus a simple transfer made in a suitable manner, from either scale to the 
other, at right angles to the axis of the rule, effects an involution or a radication to 
the second degree; and either of these operations may be combined, at will, with 
multiplication and division, by a suitable movement of the slide.* Involution and 
evolution to higher powers may also be executed by the slide-rule, though we merely 
note the fact here. 

The "slide," however, can be completely run out of the rule and re-inserted, 
when so desired, reverse side up. The reverse side of the slide bears two scales, E 
and F, these being respectively logarithmic scales of natural sines and natural 
tangents. The reverse side of the slide also carries a third scale, G, bearing equal 
divisions (l-1000ths of the scale length) and answering the purpose of a table of or- 
dinary printed logarithms, in which the numerical value of any logarithm may be 
directly read off the scale. t 

With the slide in the reversed position, the slide-rule presents the appearance 
shown in Fig. 2. When used in combination with each other, scales A, D, i/ T and F 
enable us to perform any calculation into which enter the trigonometrical functions of 
angles, combined in any way, by multiplication, division, involution or evolution, 
with quantities expressed in simple numbers. 

Our slide-rule, now fully equipped, is an instrument only a few inches long, t 
suitable for being carried in one's breast pocket, and of but trifling cost. To enum- 
erate its various uses, it at once serves as a table of numbers and their squares and 
cubes, their square and cube roots; it is at the same time a table of common logar- 
ithms of natural sines, cosines, tangents and cotangents. It is moreover capable of 
mechanically combining any of the above functions in any desired arithmetical 
combination, constantly showing up to better and better advantage the more com- 
plex the nature of the combination is. It serves also as a convenient pocket rule 
and straight edge, for it is both of these. It furthermore contains printed on its 
reverse side a valuable list of useful pocket data of many, frequently used, practical 
co-efficients. Yet while being all these things combined, alas, absolute perfection is 
unattainable! It must be admitted it has its shortcomings also. Owing to the me- 
chanical difficulty of graduation, and the uncertainty of reading results closer than 
to the third (at times the fourth) numeral place, it remains, notwithstanding all its 

* To accurately effect this transfer, a small brass part, called the "runner," is provided. See Fig. 2, A. 
This slides freely along the rule in grooves on its outer sides, and carries two indices, a, a, which accurately 
transfer points from one scale to another. 

t Scale G is really the scale of imaginary equal divisions iirst referred to as a preliminary step towards gradu- 
ating our original scale, A, A'. 

t Generally 26 centimeters, or 10 inches. 



88 MODERN SURVEYING INSTRUMENTS. 

theoretical perfection, practically an instrument only applicable where no greater 
accuracy than the third or fourth figure is required. 

Its use must always be a judicious one. The banker, computing interest or 
exchange upon extended rows of figures, will find the slide-rule falls short of his re- 
quirements. Its accuracy is inadequate in many calculations of the engineer, and 
many have undoubtedly cast the slide-rule scornfully aside, only half examined, on 
account of the only approximate accuracy of its determinations.* 

These shortcomings freely admitted, it still remains an invaluable assistant, and 
serves to good purpose wherever a limited degree of accuracy is required — and this, 
after all, holds good in the vast majority of cases in engineering practice. In con- 
struction; wherever we have to deal with practical co-efficients (generally themselves 
but approximations); where, moreover, wide factors of safety are generally intro- 
duced, and where, after all, practical considerations usually dictate a selection of the 
nearest marketable standard size — here, always, the slide-rule gives us results quite 
as reliable as the most elaborate calculation carried out to the fifth or sixth decimal 
place. In estimates of earthwork, where our surveys are at best but close approxi- 
mations to the true condition of the ground; for proportionately distributing minor 
errors; for interpolating intermediate grades; for at once transforming quantities 
expressed in one standard unit to equivalents in another standard — for all these 
purposes, on account of its great rapidity and freedom from liability to "mistakes." 
the slide-rule cannot be too highly estimated. 

It may not be equal to figuring out traverses to the one hundredth, or the one 
thousandth parts of a foot (and how very seldom do our measurements really war- 
rant such subsequent super-refinements in calculation) ; yet even here it may do 
good service as a check against " mistakes." There are hundreds of cases where its 
use in the field may obviate the many half hours and quarter hours consumed — 
with a partj T standing idle all the time — while one man alone is busy figuring out 
some field problem of location. We have, besides these cases, another frequently 
recurring set; namely, where the relations expressed in an equation are so complex 
as to make solution only practical by continued approximation; or where we have 
to assume co-efficients, themselves functions of the element to be determined; where, 
assuming some probable value of the required quantity, we gradually, by successive 
trials, adjust all elements to conformity, as so frequently occurs in hydraulic work. 
Here we can always use the slide-rule advantageously for the first stages of the cal- 
culation, and when tolerably certain of being "near the mark," we can then resort 
to ordinary modes of calculation in the last and final stage. 

From what has been said of the general accuracy of the slide-rule, one impor- 
tant corollary should be drawn: to use it successfully, that is, rapidly, we should 
never waste time in straining at the last hair, either in setting the scale or in reading 
a result; this will reap no adequate return for the extra labor spent. t 

One of the chief difficulties to beginners in using the slide-rule lies in assign- 
ing to a result its correct local value; that is, to fix the position of the decimal 
point. Many do this by rule of thumb entirely, placing the decimal point by guess- 



* Notwithstanding the above remarks, those who really make a study of it, will be astonished at the accuracy 
it can be made to yield in the hands of an adept. The slide-rule, namely, often contains in itself the means of 
overcoming its own deficiencies. Thus used, the ordinary limit of the third or fourth numeral place falls away, 
and that of tbe sixth or seventh place appears as its limit in its stead. For instance, any rapidly converging 
series applied to the rule extends its range at once immensely. This study of the ultimate possibilities of the 
slide-rule and its special applications is a highly interesting one to any one with leisure to devote to it. 

t In using the scale this is essential, as also that the slide should move with perfect freedom, though not so 
freely as to slip by an inadvertent touch. To effect this, keep the grooves clean, and, if necessary, lubricate with 
a drop of fine oil. 



THE A. LIETZ COMPANY. 89 

work, whereby mistakes are liable always to creep in. The most satisfactory method 
is to preserve in one's head the logarithmic characteristic separate, and to execute 
mentally the operation implied by the calculation, regarded as a logarithmic prob- 
lem. The result of this simple calculation always fixes the local value of the result 
correctly. For example, say 230 is to be multiplied by 0.0003, and the result divided 
by 2.7. Then we have 230 [characteristic + 2],' 0.0003 [characteristic — 4], 2.7 
[characteristic 0]; then -\- 2 -\- (— 4) — = + 2 — 4 = — 2. The slide-rule gives 
the figures of the answer to four places, 2555 (the last place a little uncertain), and 
from the foregoing we know the correct value of 230 -^- 2.7 X 0.0003 to be 0.02555. 
An additional unit must, however, always be added or subtracted every time we 
have to resort to a substitution of one index for another in attaining a result, or 
when we read a result by passing through an index (which corresponds entirely to 
carrying a unit or borrowing one where ordinary logarithms are used). A little 
practice, however, teaches us how this is to be applied. To illustrate: 56 X 7 = 392. 
If not modified, our rule would give us 1 — |— = 1, or 39.2 as an answer. To obtain 
a reading at all, a substitution of the indices was required, for which a unit must be 
added, when we have 1 -f- 4- 1 = 2, giving the correct result 392. Or, say we 
inquire how often 7 goes into 56. For the position of the decimal point, we would 
have 1 — = 1, or the answer, 80 times. We had, however, to use the right-hand 
index to obtain a reading, where ordinarily the left-hand index would have given 
us the answer. This substitution implies our subtracting an additional unit, and 
we have 1 — — 1 — 0, or 56 -^ 7 = 8, the correct answer. 

This calculation is never too difficult to be kept in one's head, save where the 
operation is a lengthy one, when it is well to keep the characteristic, as was done 
above in the process of illustration, on a separate scrap of paper, or to provide the 
slide-rule with some distinct recording device for keeping the characteristic. A 
simple device for this purpose is that of Mr. Deering, of the Southern Pacific E. K. 
A small annular disc, free to revolve around a center, upon which a radial scratch 
used as an index is marked, is provided with several radial divisions to either side 
of a central initial mark or zero. The disc is turned a suitable number of places to 
the right or left to record the characteristic, when the slide is set to the number and 
its position shifted appropriately at each stage of the operation; the index on the 
fixed center finally indicating the correct position of the decimal point. This little 
device is mounted on the runner of the slide-rule, and can be easily turned with the 
finger while one manipulates the runner. 

We will now close our observations on the ordinary slide-rule, remarking that 
figures 1 and 2 are only illustrative representations of the rule, and only show the 
main subdivisions. An idea of the fineness of the graduation actually used may be 
derived from figures 3 and 4, which show the same rule with the runner removed, 
reduced to about four-fifths the usual size. 

Besides that of Dennert and Pape the slide-rule of Le Noir has been widely in- 
troduced into this country, which, although apparently differing but slightly from 
the former, falls much short of it in practical efficiency. The most essential differ- 
ence consists in its having three of the "double scales," and only one single scale, 
instead of two of each kind — and there is no runner. Slight variations in the 
arrangements of the slide make great differences in the degree of serviceability. 

The slide-rules already described are applicable generally to all calculations, and 
there is no calculation which cannot be executed by carrying out with the rule, step 
by step, each successive intermediate operation necessary to attain the result. This, 
however, often necessitates several settings of the scale, in order to obtain a single 



90 MODERN SURVEYING INSTRUMENTS. 

result. To avoid this extended manipulation, special slide-rules maybe constructed, 
capable of solving almost any such case by one single, or at least by a greatly re- 
duced number of settings of the rule. 

Speaking generally, any function of two variables combined with constants, 
may be solved by one movement of a specially constructed rule, the peculiarity of 
the special construction being that the constants are embodied in a suitable manner 
with the variables directly. With each additional independent variable above two, 
one more movement is required, generally necessitating the introduction, however, 
of an additional scale. 

Figure 5 gives an illustration of this kind, showing a scale very widely used in 
Germany in topographical work. With stadia measurements for direct readings of 
a vertical rod, we have the formulae: 

d = K a cos - n , 
e = K a \ sin 2 n , 
where n is the angle of elevation above the horizontal ; K, a constant dependent 
upon the construction of the telescope, and generally so adjusted as to be exactly 
100; a, the reading on the vertical rod between the stadia hairs; d, the corrected 
distance of the observed point from the instrument; and e, its elevation above the 
horizontal plane through the horizontal axis of the telescope. 

In this form of slide scale, we have the slide bearing two scales; the upper scale 
graduated to \ sin 2 n, the lower one for cos 2 n. The rule carries two identically 
graduated scales of simple numbers representing the rod readings, a. Setting the 
index of the lower scale to coincidence with the rod reading, we read directly on the 
lower scale opposite the observed angle n, the corrected, i. e., horizontal distance d, 
also on the upper scale, the difference in elevation, e. 

This scale is very serviceable,* but as usually constructed is too long to be con- 
venient for anything but office use. There is another scale for the same purpose, 
executed in metal, fitted for being used in the field, a vernier being employed. In 
this case, the finer metallic graduation is relied on to make up in accuracy what 
otherwise would be sacrificed by the reduced length of the scale. 

Another direction presents itself for development of the slide-rule by artificially 
extending the length of unit (without correspondingly increasing the size of the in- 
strument). In his catalogue of instruments, Stanley of London, describes an in- 
strument by Professor Fuller. Here, by developing the scales on a spiral line 
upon a cylinder, a length of unit equivalent to 83 feet is attained, of course, hereby 
very materially increasing the accuracy of the slide-rule, although probably not 
nearly in the ratio of the increased length (which is about one hundred-fold that of 
the ordinary slide-rule). 

* This scale is also very convenient in running grade lines, enabling the transit-man always to select his grade 
points on the ground, and keep track of his elevations without the aid of the level, and judiciously used will 
often save much "backing up " in field location. 



No. 3. 

SOME PRACTICAL HINTS 

ON 

How to Tell a Good Surveying Instrument 

By A. LIETZ, Member Tech. Soc. 



Kegarding their quality, engineers' instruments may be divided into two classes. 
In the first category we would place those which are disposed of by their makers 
directly to the engineer who uses them, while those of the second class are made 
for the trade, and sold principally by dealers. While in most of the latter class 
many so-called improvements are introduced that make them easily salable, they do 
not possess the thorough workmanship which makes up a first-class article. There 
are, indeed, many improvements, which may yet be added, but if they are not made 
in a thorough workmanlike manner they are of little, if any, importance, and will 
in no case make an instrument of fine quality. 

Graduation. — In a transit, the graduation is the most important part. Solid 
silver is the best metal known, upon which a perfect graduation can be made, and 
it is therefore almost exclusively used by makers. It has the advantage of keeping 
its surface better than the silver wash, which is found on most of the older instru- 
ments. 



To examine the graduation, the first thing should be to see whether each line 
is perfectly sharp and clearly cut; for this purpose it is well to use a compound mi- 
croscope, as only a very keen observer will be able to detect unevenness in the lines 
with a common magnifier. The starting point of a line, if closely examined, will 
show whether a perfectly-shaped and well-set tool was used in cutting it. 

The line shown in figure A, in which the upper or pointed end is the starting 
point, indicates by its true shape that it could only have been made with a perfect 
and properly set tool. It is a fact that this shape is found in all graduations of 
first-class instruments. 

* Reprinted and revised, by permission, from the Transactions of the Technical Society of the Pacific 
Coast, Vol. VII, No. 5,- December, 1890. 



92 MODERN SURVEYING INSTRUMENTS. 

In Fig. B the line has no taper, but begins with its full width. In such an 
event the cut was either made from the inner rim of the circle outward, or, what is 
more likely, the engraving tool was set end for end and drawn from the starting 
point backwards toward the center. In most cases is the blunt end of the line ex- 
plained by the latter method. Although the tool used for such a purpose may have 
been sharp and of the proper form, the additional pressure required to draw it with 
its wrong end foremost vitiates the degree of accuracy of the graduation, for, if an 
unnecessary force is applied in producing a line, the tool will not always follow the 
motion in which it is guided by its drawing mechanism. 

Figure C represents a line made with an imperfect drawing device and a dull 
tool not capable of doing good work. 

It will be noticed in figures A, B and C, that the starting point of the line shows 
the shape of the tool with which it was made, and this is, therefore, the main point 
upon which to pass judgment on the value of a graduation. 

After we have convinced ourselves that the shape of the line is perfect, we may 
feel somewhat assured that the graduation is a good one; but if the lines are not 
equally spaced, they are worthless. To determine this is the most difficult as 
well as the most tedious of tests to be made in the examination of an instrument 
with graduated circles. The manufacturers have apparatus with which such exam- 
inations can be made in a comparatively short time, and with a great degree of 
accuracy. No maker of first-class instruments will let one go out of his hands be- 
fore having convinced himself that the divisions are as perfect as demanded by the 
character of the article. 

The most accurate graduation, however, is of no value without a well-fitting 
center. To prove both, several methods are employed. The surest test is to clamp 
the vernier plate to any point of the circle, then, if by adding the reading of the 
two verniers together — frequently repeating this manipulation upon different parts 
of the circle — the sum will always be 180 degrees, they are correct. (This refers to 
plates graduated from to 180 degrees, on both sides of zero; in case of a graduation 
to 360 degrees, a subtraction is required.) 

The graduation of an instrument having but one vernier can only be tried with 
the telescope, which is a rather tedious operation. 

It may also be remarked, that short lines on a graduated circle are of some ad- 
vantage, as the spaces between them appear to be much larger, and there is conse- 
quently less fatigue to the eye while reading. It is another fact that during the 
process of graduating the tool is not required to do as much work, and is therefore 
apt to keep its fine edges better, thereby securing more perfect work. 

The space between the circle and verniers must be very small if an accurate 
reading is to be obtained; it must appear through a reading glass like a very fine 
black and uniform line, and should remain so during the revolution of the circle. 

In second-class instruments it is generally found that the verniers and circles 
are not set in the same plane; this is done to make any unevenness in the plate dis- 
appear, but it is a very objectionable feature, for it will cause parallax, and no 
accurate reading can be taken with such circles. 

The Telescope. — The telescope forms a very important part of an instrument, 
and must, therefore, be closely examined. The reason why so many telescopes of 
second-class instruments are called good is because they have a very low magnifying 
power, and consequently will give a good definition; but if the magnifying power of 
such telescopes were to be increased to what it should be, with the same kind of 
glasses and workmanship, the definition would be entirely lost. Experience has 



THE A. LIETZ COMPANY. 93 

shown that a telescope of 11£ inches length, such as is generally used in transits of 
the ordinary size, may have a magnifying power of twenty-four diameters, and 
give a good definition and sufficient light, if the new Jena glass is used; while most 
telescopes of the same size, which I have had occasion to examine, show, on an av- 
erage, a magnifying power of fifteen diameters only. It is true that a low power 
may be of advantage under certain atmospherical conditions, but, as a rule, a higher 
power will give better satisfaction if the lenses are first-class. 

Inverting telescopes, which are used almost exclusively in European countries, 
are comparatively little in vogue in the American engineering fraternity. They have 
a great advantage over the erect telescopes; the eye-piece having two lenses only and 
being shorter, the proportion between the focal lengths of the objective lens and the 
eye-piece may be increased considerably, and thusly the magnifying power, without 
loss of light. 

Construction. — In regard to the construction, it is the aim of every maker to 
build an instrument of the least weight, it being limited only to the extent that it 
shall not be affected by the wind and become unsteady by reason of its lightness. 
While it is reasonable that a proper reduction can best be effected by decreasing the 
size of the whole instrument, instead of reducing the weight of individual parts of 
a large transit, for instancej great possibilities in this direction are open by a ju- 
dicious use of aluminium in the manufacture of instruments. The author firmly 
believes that with this metal we shall be able to reduce the weight considerably, 
without any sacrifice of steadiness, and it is his purpose to make some detailed in- 
vestigations in the near future that shall lead to an intelligent understanding of 
this subject. 

The steadiness of an instrument depends upon its construction; those that 
have the longest centers, with the shortest distance between the tripod-head and 
the plates, and in which the distance between the leveling screws is large enough to 
secure a proper base, or, in other words, a strong foundation, will prove to be firm 
and steady even in a strong wind. 

The methods of placing the verniers of a transit in such a position that they 
may be read without stepping aside while observing, is a feature in construction 
which has been pronounced objectionable, because the size of the plate level, which 
is at right-angles to the line of collimation, and which is the more important of the 
two,*has to be reduced. The manner in which this can be overcome without 
reducing its length, or without placing it over one of the verniers (which must 
affect the degree of accuracy of the reading considerably), and the way in which 
this level may be set without allowing it to extend beyond the circumference of 
the plate, will be explained on some other occasion. 

The Compass. — The compass should be made as large as possible, but without 
reducing the value of more important parts. It can often be noticed that an instru- 
ment with very large compass has the telescope standards fastened too far from 
the center, which reduces steadiness; while others, of course still worse, have much 
spare room between standards and compass box. The point of the center-pin, as 
well as the upper ends of the needle, must lie in the same plane with the gradua- 
tion, if the quivering motion which most sensitive needles possess, shall not be 
noticed on the reading points. As the accuracy depends principally on the pin and 
cap, these should consist of the best material, while the lift arrangement must be 
constructed in such a manner as to raise and lower the needle gently, in order to 
prevent the sudden jerking and falling, which is so often the cause for the rapid 
wearing out of the point and cap. 



94 MODERN SURVEYING INSTRUMENTS, 

Other Details. — It is an important feature of most all of the later instruments 
that the clamp by which the horizontal circle is held in position works toward the 
center on a collar, instead of being clamped on the circumference of the plate, and 
that all tangent screws are provided with opposing springs. 

It is also important that the telescope standards have bases large enough to 
secure proper connections with the plate. It is, furthermore, of great importance 
to insure steadiness that the lower parts containing the leveling screws be made out 
of one solid star-shaped casting, instead of the common round plates into which 
the nuts are simply stuck. There seems to be no other reason for making this lat- 
ter style than to save a few dollars in labor. 

If the star-shaped piece is slotted and provided with clamp screws, lost motion, 
which is liable to appear in time in the leveling screws, can be taken up. 

It goes without saying that all transit instruments should be provided with 
shifting centers, that ought to be protected by a thin metal plate, to keep the 
dust out. 

The Tripod. — The tripod legs must be light and strong, and of good hard 
wood, in order to secure steadiness, and should be fitted from the outside, so that 
any shrinkage of the wood may be drawn up by a nut at any time. In the older 
style, where the legs fit inside, this cannot be accomplished, and in that case it not 
only reduces the steadiness, but may also lead to serious accidents. The split or 
skeleton legs are best suited to come up to all the requirements of a good tripod. 

The Case. — The manner in which an instrument is packed in its case is by no 
means unimportant. A transit must stand upright, so that it may be taken out by 
holding the lower base-plates and leveling screws, and not the upper plates or the 
telescope axis. A Y- level box should be provided with an extra space for the tele- 
scope to rest in upon its collars. 

The finish. — The outer finish of an instrument, although having little to do with 
its accuracy, will always be found of some elegance in a first-class article. Un- 
fortunately, most of the second-class possess a brilliant finish that only too often 
leads purchasers to overlook the more important parts. If engineers, when select- 
ing instruments, would thoroughly test the finer qualities, and take into con- 
sideration the construction, they would not only be certain to get a more perfect 
article, but would induce makers to construct and build instruments in accordance 
with scientific principles. 

DISCUSSION 

By Mr. Luther Wagoner. 

The paper is a good practical resume of the principal points concerning the 
working qualities of a field instrument, and I presume it refers solely to the selec- 
tion of a new article. 

My experience is that instruments do not often retain the good points shown in 
the shop after the ordinary usage and almost inevitable rough handling in the field 
and especially in transportation. 

These injuries are usually springing or bending of the centers and eccentricity; 
that is, the two axes are not co-incident, and the latter condition is one common to 
nearly all instruments in a greater or less degree. I have seen it large enough to 
cause an error of three minutes in a right-angle. 

As it may be necessary to try to do good work with such an instrument, I will 
explain my method of examining an instrument having two verniers. 






THE A. LIETZ COMPANY. 



95 



Set one vernier at zero and read the other, calling less than 180 degrees minus 
and more than 180 degrees plus; take such readings, say, every 15 degrees on the 
circle and tabulate them properly. The mean of all the readings will be the angular 




difference of the verniers from 180 degrees; subtract this mean quantity from each 
of the original readings (having due regard to the algebraic signs), and then use the 
resultant new column, as follows: 

With any convenient radius draw a circle on a cardboard and divide the circle 
into as many parts as there are observations, numbering the card like the instru- 
ment; then using the circle as a base-line, plot the resultant new column, calling 
inside radical lines minus and outside radical lines plus, using any convenient scale; 
join the points thus plotted, and cut out with a sharp knife the resultant figure, as 
shown in the accompanying engraving by shaded lines; balance it over a knife-edge 
in two or more positions, and mark the center of gravity thus found. Eeplace the 
figure in the cardboard, and with the original radius and center of gravity as a new' 
center draw a circle. (See figure.) The variations from this new circle are the 
residual errors due to graduation and observation. 

Unless an instrument was either very poor originally, or has been very roughly 
handled, these residuals should not exceed a few seconds. 

The center of gravity found by the above method is the vernier-plate axis; its 
distance from the original center is the amount of eccentricity measured by the 
scale used for plotting the figure, and a line drawn through the two axes gives its 
direction. 



No. <4. 



THE GOLDSCHMID ANEROID.* 



It need hardly be stated that all aneroid barometers make use of the elasticity 
of a hermetically sealed box, or other closed compartment in which a partial vacuum 
has been established, to measure changes in atmospheric pressure. The movements 
of the bos, always small, are magnified by means of a somewhat complex system of 
delicate levers in the ordinary aneroid forms, of which that of Naudet's make may 
be taken as a type. The extreme delicacy of the intermediate transmission has 
always proved the objectionable feature and the main source of inaccuracy, and it 
was with the object of totally suppressing this transmission that Goldschmid suc- 
cessively designed the series of instruments which bear his name. 

The movements of the vacuum box were observed either by a micrometer screw 
or, as in the Goldschmid- Weilenmann's aneroid, several boxes are mounted, one 
upon another, the upper end of the series carrying an index, whose motion is ob- 
served by a minute telescope provided with cross-hairs, and mounted upon a 
micrometer screw. 

The original instrument with a single box proved deficient in delicacy, and the 
compound-box aneroid disappointed the expectations of its designers in not pos- 
sessing the requisite qualities of standing ordinary rough handling in shipment or 
field use. While giving admirable results when left stationary or carefully carried 
upon an observer's person, curiously enough this compound-box aneroid (No. 3) 
showed that sudden jars produced very considerable changes in the instrument — 
not abrupt changes only, but changes such that often weeks and months were re- 
quired before the boxes again assumed a state of equilibrium. This deficiency was 
all the more surprising on account of the construction having been so simple, and 
all intermediate transmission having been eliminated, that special freedom from 
liability to disarrangement had been confidently anticipated. 

Since Goldschmid's death his successor, Hottinger, of Zurich, has continued his 
investigations, and, after many modifications and changes, has produced the type 
of instruments shown in figures 1, 2 and 3, known as the Goldschmid Aneroid No. 1. 
The vacuum, b b (Figs. 1 and 2), is kept in tension by the steel spring,//; this 
transfers the movement of the box-center to the lever, h h, turning on the fulcrum, 
a. To the top of this lever, h h, is attached a hair-spring, e e. The movements of 
the box are measured by means of a micrometer screw, 31, whose contact with the 
hair-spring, e e, must be ascertained with greater accuracy than is possible by the 
mere sense of touch, and is accordingly indicated by the coincidence of two black 
lines on the heads of the lever, h h, and the hair-spring, e e, observed by means of 
a magnifying glass, L. The scale, S S (Fig. 3), gives the full revolution of the 
micrometer screw. The first instruments of this class were provided with a scale 
on which the readings increased with the altitude, the value of the scale-unit being 
arbitrary. The scale of the more recent instruments is divided to correspond with 

* From Specht's description of the instrument and from Hottinger's illustrations. 



THE A. LIETZ COMPANY. 97 

the mercurial barometer. Each revolution of the micrometer screw corresponds to 
10 mm. of the mercury column, and the head of the micrometer screw is decimally 
graduated, admitting of accurate reading to the one-hundredth part of a millimeter. 

The usual size of this instrument is 3£ inches diameter and 1\ inches high. 
Fig. 1 is a vertical section; Fig. 2, a top view, the cover being removed; Fig. 3, a 
side view; g g is the outer shell; r r the revolving and graduated head; h', Fig. 1, the 
end of the main lever, and e' that of the hair-spring lever, each provided with an 
index-line; £ S, Fig. 3, the scale by which the number of full revolutions of the 
micrometer screw, M, Fig. 1, are measured. 

New aneroids give elevations at the ordinary atmospheric pressure (25 to 30 
inches) correctly within one-half of one per cent., the difference of elevation not 
being more than 750 to 1,000 feet. For the determination of greater differences of 
elevation old aneroids should be used, in which the box has attained its equilibrium. 
Indeed, it may be said that the instruments improve with age. 

. The influence of temperature upon 44 of these aneroids, tested for a period of 
six months, at temperatures of 10° to 30° C. (50° to 86° Fahr.), was only 0.4 mm. per 
1° C. 

Each instrument is provided with a table of reduction, giving the value of its 
unit at different atmospheric pressures in millimeters, or inches of the mercurial 
barometer, and its value in inches or feet, and the corrections for temperature. 
Each is rated individually and tested daily for four months at the factory before be- 
ing sent out. No. 2 differs slightly from No. 1 in construction; is considerably 
smaller, and less sensitive, and is better adapted for tourists than for engineers. Its 
probable error is nearly double that of No. 1. 

In the aneroid No. 3 (Weilenmann's system), the small telescope already referred 
to is mounted upon a micrometer screw, which measures its movement. The 
cross-hairs of the telescope being brought into coincidence with the index on the 
upper of the combined' series of boxes, the scale of the micrometer indicates directly 
the motion of the boxes in terms corresponding to the movements of the mercurial 
barometer. 

The boxes are entirely independent of the micrometer screw, so that no changes 
in the instrument can occur by reason of wear on the point of the micrometer, or 
any other part. Its accuracy is so great that it can fully replace the mercury bar- 
ometer at atmospheric pressure below 24 inches, and it is much more portable. Its 
size is 6 inches high by 3 inches diameter. 

Self-Registering Aneroid or Barograph. 

The purpose of this instrument is to register automatically the readings of the 
aneroid, which consists of a number of boxes like the one just described, the move- 
ments being transferred by a lever to a paper on a drum revolved by clock-work. 
Every hour a point is marked upon this paper, giving the reading of the aneroid. 
After 48 hours a paper 3 inches long is unwrapped, containing 48 equidistant points 
1£ mm. apart. The dimensions of this instrument are such that the maximum 
motion of the pointer is 2 inches, corresponding to the same movement of the mer- 
curial barometer. Two-tenths of a millimeter can be read with certainty. 



No. 5. 

A SHORT AND PRACTICAL METHOD 

To find the length of one minute of Longitude in any Latitude, 

based upon certain Developments of the Terrestrial Spheroid. 
By Otto von Geldern. 



For the determination of arcs of the Parallel and Meridional arcs, certain ele- 
ments of the terrestrial spheroid have been used. 

Up to within the last ten or fifteen years, Bessel's determinations of the earth's 
magnitude were employed, which were: 

Equatorial Kadius, a = 6,377,397 meters, 
Polar Kadius, . b = 6,356,079 meters, 

Compression = 

299.153 

Upon these elements the usual tables for the polyconic projection of maps were 
based, until those of Col. A. K. Clarke, E. E., were adopted, which furnish results 
more in harmony with recent geodetic measurements. Colonel Clarke's researches 
were published in his Comparison of the Standards of Length of England, France, 
Belgium, Prussia, Russia, India and Australia, made at the Ordnance Survey Office, 
Southampton, 1866. 

The U. S. Coast and Geodetic Survey has adopted the Clarke form, and pub- 
lished a long and carefully computed series of polyconic projection tables for it in 
1884, which are still in use. (See Appendix No. 6, Keport 1884.) 

Limiting the figure to that of an ellipsoid of revolution, Clarke's values are: 
a = 6,378,206 meters, 

exceeding Bessel's 809 m 
b — 6,356,584 meters, 

exceeding Bessel's 505 m - 

Compression 

F 294.98 

It shows that this spheroid is somewhat larger than Bessel's and that the eccen- 
tricity is also greater. 

These elements have satisfied the conditions developed during scientific meas- 
urements of large areas, so that they may be safely adopted without fear of appreci- 
able error. 

It is not the present purpose to enter into the subject mathematically. 

If the earth were a perfect sphere with a radius R, the expression for the value 
of one minute of longitude in any latitude would be 

cos lat. _ — 

360 X 60 

Assuming K equal to the length of the equatorial radius, 6,378, 206 meters, the 

constant 1855.3 is obtained for the second member. By this constant the cosine of 

the latitude would have to be multiplied, in order to determine the length of one 

minute of longitude in meters. Or logarithmically expressed it is: 

log. cos lat. + 3.2684256. 

As we are dealing with a compression of nearly however, it becomes neces- 

1 J 300 



THE A. LIETZ COMPANY. 99 

sary to take some recognition of this fact in the determination of distances on the 
parallel. For our present purpose it will answer if we find a method that shall 
furnish results approaching the truth within reasonably narrow limits, without 
considering exact mathematical formulae for obtaining very great precision. 

After a careful study of this subject, based upon comparisons with very exact 
tabular values, the following method is proposed by the author, who has had occa- 
sion to make frequent use of it. 

APPROXIMATE METHOD. 

If the length of one minute of arc on the parallel be required, that shall not 
vary greatly from the correct value, observe the following rule: 

To the logarithmic constant 3.2684256 add the logarithmic cosine of any given 
latitude less 5 minutes, and the result will be the length in meters of one minute of 
longitude in'the given latitude. 

Example: — What is the length of one minute of longitude in latitude 37° 47' ? 
Log. constant, . . . 3.2884256 

Log. cosine of latitude 37° 42' 9.8982992 
(37° 47' _ 05' =37° 42') 3.1667248 

Answer, 1468.0 meters. 
(Correct within 0. 2m.) 
By this method results are obtained correct within 0. 3 m - from the equator up 
latitude 60°; from 60° to 70° within 0. 5 m ; beyond that limit the deviations from 
the true values grow more rapidly, yet even at 80° a minute of longitude thus ob- 
tained would have an excess of 1. 6 m - only. For all ordinary requirements, there- 
fore, the above rule will apply. 

A deduction of an even 5 minutes gives the best average results, and for that rea- 
son it has been adopted. If we want to be a little more precise about it, we may 
use 4 minutes from to latitude 25°, and from 65° upwards; 5 minutes from 25° to 
35°, and from 50° to 65°; and 6 minutes from 35° to 50°. With this precaution the 
results will not vary more than 0. 2 m - for any case from the equator up to latitude 
70°. 

If the distance is desired in feet instead of meters, multiply the result by 3.28087, 
or use the logarithmic constant 3.7844146 instead of the one given above. 

A MORE ACCURATE METHOD. 

Where greater refinement is required, say that instead of one minute we should 
want the length, of one degree of arc without appreciable error, the deductions from 
the latitude must be defined a little more closely still, if they shall furnish reliable 
results. 

By using the deductions given in minutes and seconds in the table below, for 
every 5° of latitude, results may be obtained that will be without appreciable devi- 
ation from the truth, even in the case of the. length of one degree on a parallel. 
In latitude 0° deduct 0' 0". 
5° " V 00". 

10° " V 50". 

15° " 2' 40". 

20° " 3' 50". 

25° " 4' 30". 

30° " 5' 00". 

35° " 5' 30". 

40° " 5' 40". 



Cn latitude 


45° 


deduct 


5' 50". 


" 


50° 


" 


5' 40". 


" 


55° 


" 


5' 30". 


i i , n 


60° 


" 


5' 00". 


a a 


65° 


1 1 


4' 30". 


a a 


70° 


" 


3' 50". 


" 


75° 


n 


3' 00". 


it it 


80° 


1 1 


2' 00". 



100 MODERN SURVEYING INSTRUMENTS, 

Any intermediate value may be interpolated. 

Referring again to the previous example, let us find the value of one minute of 
longitude in latitude 37° 47' by this method. 

By consulting our table we find that for 37° 47' we must deduct 5' 35", leaving 
37° 41 ' 25". Then write: 

Log. constant, .... 3.2684256 
Log. cosine of latitude 37° 41' 25", 9.8983724 



3.1667980 
Answer, ....... 1468.2 meters. 

(Which is correct to the nearest tenth.) 
If the length of a degree is wanted, multiply the result by 60, or use the con- 
stant 5.0465769 instead of the one above given. 

Example: — What is the length of one degree of longitude in latitude 17°? 

Log. constant, . 5.0465769 

Log. cosine 16° 56' 45", 9.9807216 

(17°— 3' 15") 5.0272985 

Answer, ....... 106,487 meters. 

(Which is correct to the nearest meter.) 
Again, for latitude 74°? 

Log. constant, . 5.0465769 

Log. cosine 73° 56' 50", 9.4417308 



4.4883077 
Answer, . . . . . . . 30,782 meters. 

(Correct within 1 meter.) 
These results are readily reduced to either nautical or statute miles, by dividing 
by 1853.248 (log. 3.2679335) in the former, and by 1609.33 (log. 3.2066449) in the 
latter case. The logarithmic constant may be changed to suit these measures. 

THE NAUTICAL MILE. 

The length of a nautical mile has been adopted at 1853.248 meters, or 6080.27 
feet. It will be noticed that this is 2.1 meters less than the length of one minute of 
longitude at the equator, which is ordinarily assumed as that which defines the 
nautical mile. The fact is that this unit of measure has been arbitrarily based, and 
that it varies as the data from which the deductions are made. In order to estab- 
lish uniformity for all time, the nautical mile is now defined as the length of one 
minute of a great circle of a sphere that shall have the same superficial area as the 
terrestrial spheroid. This basis was adopted by the U. S. Coast and Geodetic Sur- 
vey, and computed from Clarke's elements. 



Length of One Minute of Latitude in Different Latitudes. 



At the Equator, . . 1842.8 meters At 50°, . . . 1853.8 meters 

" 10°, . . . 1843.4 " " 60°, .... 1856.9 " 

" 20°, .... 1845.0 " " 70°, . . . 1859.4 " 

" 30°, . . . 1847.5 " " 80°, .... 1861.1 " 

" 40°, .... 1850.5 " " 90°, . . . 1861.7 " 






No. 6. 



The 

SAEGMULLER SOLAR ATTACHMENT 



VERTICAL SIGHTING TELESCOPE. 

(Patented May 3, 1881.) 

How to Adjust and Use It, with Refraction Tables. 



THE A. LIETZ COMPANY, 

Sole Agents on the Pacific Coast of the Saegmiiller Solar. 
San Francisco, Cal., 1893. 



This attachment to the regular engineer's transit, by means of which the astro- 
nomical meridian may be obtained in a few minutes with an accuracy scarcely thought 
to be possible, has met with such success that it bids fair to supersede all other 
methods for the determination of the meridian by means of engineering instruments. 

The transit has come to be the universal instrument for the engineer, and will 
be for the surveyor sooner or later, and the attachment of the solar apparatus to the 
transit has thus become a necessity. 

Since its first introduction this attachment has been greatly improved, and, as 
now made, is nearly perfect. 

Attached to any transit which possesses a telescope, level and a vertical circle, it 
will give the meridian within the nearest minute. By using instruments which have 
a finer graduated vertical circle and better levels than are usually found on transits, 
the meridian can be determined with greater accuracy still. 

Advantages of the "Saegmuller Solar Attachment" over the Old Form. 

First. — It is more accurate. 

Second. — It is simpler and easier of adjustment. 

Third. — It can be used when the sun is partly obscured by clouds, when the 
ordinary "solar " fails altogether. 

Fourth. — It can be used where the sun is quite close to the meridian. 

Fifth. — The time can be obtained with it reliable to within a few seconds with 
perfect ease. 

Sixth. — It can be used as a vertical sighting telescope. 

It is as superior to all forms hitherto used as the transit is to the ordinary com- 
pass, or as a telescope is to common sights. 

* Reprinted by permission, and revised for this Manual. 



102 MODERN SURVEYING INSTRUMENTS, 

The sights of an ordinary solar compass consist merely of a small lens and a 
piece of silver with lines ruled on it placed in its focus. This is simply a very 
primitive telescope, since the exact coincidence of the sun's image with the lines 
has to be determined by the unaided eye, or at best with a simple magnifying glass. 

That far greater precision can be attained by means of a suitable telescope is 
obvious; in fact, the power of the solar telescope is in keeping with the transit tel- 
escope, as it should be. 

A glance at the illustration will show that the "Saegniiiller Solar Attachment" 
is far simpler than the ordinary form. By raising or depressing, it can be set to 
north or south declination. To effect this with the ordinary solar compass two sets 
of primitive telescopes — one answering for north, the other for south declination — 
are required, which are difficult to adjust. 

The addition of the level on the solar telescope dispenses with the declination 
arc altogether, the arc or circle on the transit also serving for that purpose in con- 
junction with it. 

The " Saegmuller Solar Attachment " is, in fact, the only one which should be 
used in connection with a transit instrument. It solves the solar problem, as has 
been attested by leading astronomers and engineers who have used it. 

Professor J. B. Johnson, of Washington University, St. Louis, Mo., has given 
it a thorough test, and writes as follows: 

" In order to determine just what accuracy was possible with a Saegmuller Solar 
Attachment, I spent two days in making observations on a line whose azimuth had 
been determined by observations on two nights on Polaris at elongation, the instru- 
ment being reversed to eliminate errors of adjustment. Forty-five observations 
were made with the solar attachment on October 24, 1885, from 9 to 10 a.m., and 
from 1:30 to 4 p. m., and on November 7, forty-two observations between the same 
hours. 

' ' On the first day's work the latitude used was that obtained by an observation 
on the sun at its meridian passage, being 38° 39', and the mean azimuth was 20 
seconds in error. On the second day, the instrument having been more carefully 
adjusted, the latitude used was 38° 37', which was supposed to be about the true 
latitude of the point of observation, which was the corner of Park and Jefferson 
avenues in this city. It was afterwards found that this latitude was 38° 37' 15", as 
referred to Washington University Observatory, so that when the mean azimuth of 
the line was corrected for this 15" error in latitude, it agreed exactly with the stellar 
azimuth of the line, which might have been 10" or 15" in error. On the first day all 
the readings were taken without a reading glass, there being four circle readings to 
each result. On the second day a glass was used. 

" On the first day the maximum error was 4 minutes, the average error was 0.8 
minute, and the 'probable error of a single observation' was also 0.8 minute. On 
the second day the maximum error was 2.7 minutes, the average error was 1 minute, 
and the ' probable error of a single observation ' was 0.86 minute. The time re- 
quired for a single observation is from three to five minutes. 

" I believe this accuracy is attainable in actual practice, as no greater care was 
taken in the adjustment or handling of the instrument than should be exercised in 
the field. 

" The transit has come to be the universal instrument for the engineer, and 
should be for the surveyor; so it is more desirable to have the solar apparatus at- 
tached to the transit than to have a separate instrument. The principal advantages 
of this attachment are: 



THE A. LIETZ COMPANY. 



103 



" 1. Its simplicity. 

" 2. Its accuracy of pointing, being furnished with a telescope which is accu- 
rately set on the sun's disk. 

"3. In its providing that all angles be set off on the vertical and horizontal 
limbs of the transit, thus eliminating the eccentricity and other inaccuracies usually 
found in attachment circles or arcs. 

"4. Its small cost. 

" It is also readily removed and replaced without affecting its adjustments, and 
is out of the way in handling and reversing the telescope. It may be attached to 
any transit." 




SAEGMULLER SOLAR ATTACHMENT. 

This instrument may be had in ALUMINIUM, which gives that lightness 
particularly desirable in an attachment of this character. 

The illustration represents the improved " Saegmiiller Solar Attachment " as now 
made. It consists essentially of a small telescope and level, the telescope being 
mounted in standards, in which it can be elevated or depressed. The standard re- 
volves around an axis, called the polar axis, which is fastened to the telescope axis 
of the transit instrument. The telescope, called the " Solar Telescope," can thus be 
moved in altitude and azimuth. Two pointers attached to the telescope to approx- 
imately set the instrument, are so adjusted that when the shadow of the one. is 
thrown on the other the sun will appear in the field of view. 



ADJUSTMENT OF THE APPARATUS. 

1. The transit must be in perfect adjustment, especially the levels on the tele- 
scope and the plates; the cross-axis of the telescope should be exactly horizontal, 
and the index error of the vertical circle carefully determined. 

2. The polar axis must be at right-angles to the line of collimation and 
horizontal axis of main telescope. 

To effect this, level the instrument carefully and bring the bubble of each tele- 
scope level to the middle of its scale. Kevolve the solar around its polar axis, and 



104 



MODERN SURVEYING INSTRUMENTS. 



if the bubble remain central, the adjustment is complete. If not, correct half the 
movement by the adjusting screws at the base of the polar axis, and the other half 
by moving the solar telescope on its horizontal axis. 

3. The line of collimation of the solar telescope and the axis of its 
level must be parallel. 

To effect this, bring both telescopes in the same vertical plane and both bubbles 
to the middle of their scales. Observe a mark through the transit telescope, and 
note whether the solar telescope points to a mark above this, equal to the distance 
between the horizontal axes of the two telescopes. If it does not bisect this mark, 
move the cross-wires by means of the screws until it does. Generally the small 
level has no adjustments, and the parallelism is effected only by moving the cross- 
hairs. 

The adjustments of the transit and solar should be frequently examined, and 
kept as nearly perfect as possible. 

DIRECTIONS FOR USING THE ATTACHMENT. 

First. — Take the declination of the sun as given in the Nautical Almanac * for 
the given day, and correct it for refraction and hourly change. Incline the transit 
telescope until this amount is indicated by its vertical arc. If the declination of the 
sun is north, depress it; if south, elevate it. Without disturbing the position of 
the transit telescope, bring the solar telescope into the vertical plane of the large 
telescope, and to a horizontal position by means of its level. The two telescopes 
will then form an angle which equals tlie amount of the declination, and the incli- 
nation of the solar telescope to its polar axis will be equal to the polar distance of 
the sun. 

Second. — Without disturbing the relative positions of the two telescopes, incline 
them and set the vernier to the co-latitude of the place. 

By moving the transit and the "Solar Attachment" around their respective 
vertical axes, the image of the sun will be brought into the field of the solar tele- 
scope, and after accurately bisecting it, the transit telescope must be in the meridian, 
and the compass-needle indicates its deviation at that place. 

The vertical axis of the "Solar Attachment" will then point to the pole, the 
apparatus being in fact a small equatorial. 

Time and azimuth are calculated from an observed altitude S 
of the sun by solving the spherical triangle formed by the sun, 
the pole, and the zenith of the place. The three sides, S P, 
P Z, Z S, complements respectively of the declination, latitude 
and altitude, are given, and we hence deduce S P Z, the hour 
angle, from apparent noon, and P Z S the azimuth of the sun. 

The "Solar Attachment" solves the same spherical triangle 
by construction, for the second process brings the vertical axis 
of the solar telescope to the required distance, Z P, from the 
zenith, while the first brings it to the required distance, S P, 
from the sun. 

OBSERVATION FOR TIME. 

If the two telescopes, both being in position — one in the meridian, and the 
other pointing to the sun — are now turned on their horizontal axes, the vertical 




A Nautical Almanac must be a part of the engineer's field outfit. 



THE A. LIETZ COMPANY. 



105 



remaining undisturbed, until each is level, the angle between their directions (found 
by sighting on a distant object) is S P Z, the time from apparent noon. 

This gives an easy observation for correction of time-piece, reliable to within a 
few seconds. 



TO OBTAIN THE LATITUDE WITH THE 

ATTACHMENT." 



SAEGMULLER SOLAR 



Level the transit carefully and point the telescope toward the south, and elevate 
or depress the object end, according as the declination of the sun is south or north, 
an amount equal to the declination. 

Bring the solar telescope into the vertical plane of the main telescope, level it 
carefully and clamp it. With the solar telescope observe the sun a few minutes 
before its culmination; bring its image between the two horizontal wires by moving 
the transit telescope in altitude and azimuth, and keep it so by the slow-motion 
screws until the sun ceases to rise. Then take the reading of the vertical arc, cor- 
rect for refraction due to altitude by the table below. Subtract the result from 90°, 
and the remainder is the latitude sought. 



Mean Refraction. 
Barometer 30 inches, Fahrenheit thermometer 50 degrees. 



Altitude. 


Refraction- 


1 

Altitude. 


Refraction . 


10° 


5' 19" 


20° 


2' 39" 


11 


4 51 


25 


2 04 


12 


4 27 


30 


1 41 


13 


4 07 


35 


1 23 


14 


3 49 


40 


1 09 


15 


3 34 


45 


58 


16 


3 20 


50 


49 


17 


3 08 


60 


34 


18 


2 57 


70 


21 


19 


2 48 


80 


10 



The following table, computed by Prof. Johnson, C. E., Washington University, 
St. Louis, will be found of considerable value in solar compass work: 

"This table is valuable in indicating the errors to which the work is liable at 
different hours of the day and for different latitudes, as well as serving to correct 
the observed bearings of lines when it afterwards appears that a wrong latitude or 
declination has been used. Thus on the first day's observations I used a latitude 
in the forenoon of 38° 37', but when I came to make the meridian observation for 
latitude I found the instrument gave 38° 39'. This was the latitude that should 
have been used, so I corrected the morning's observations for two minutes error in 
latitude by this table. 

"It is evident that if the instrument is out of adjustment the latitude found 
by a meridian observation will be in error; but if this observed latitude be used in 
setting off the co-latitude, the instrumental error is eliminated. Therefore, always 



106 



MODERN SURVEYING INSTRUMENTS. 



use for the co-latitude that given by the instrument itself in a meridian observa- 
tion." 

Errors in Azimuth (by Solar Compass) for 1 Minute Error in Declination or Latitude. 



Hour. 



For 1 Mix. Error in Declina- 
tion . 



11:30 a. m... \ 
12:30 p. m... J 



11 A. M. 
1 P. M. 



10 A. M. 
2 P. M. 



9 A. M \ 

3 P. M J 



Lat. 30° 



MIN. 

8.85 
4.46 
2.31 



Lat. 40 c 



MIN. 

10.00 
5.05 
2.61 



Lat. 50° 



a a. m. 

4 P. M, 



::} 

7 A.M "J 

5 P. M J 

::} 



1.63 1.85 

1.34 



6 A. M. 
6 P. M. 



1.20 



1.15 



1.51 
1.35 
1.30 



MIN. 

12.90 
6.01 
3.11 
2.20 
1.S0 
1.61 
1.56 



For 1 Mix. Error in Lati- 
tude. 



Lat. 30 c 



MIN. 

8.77 
4.33 
2.00 
1.15 
0.67 
0.31 
0.00 



Lat. 40° 



MIN. 

9.92 
4.87 
2.26 
1.30 
0.75 
0.35 
0.00 



Lat. 50° 



MIN. 

11.80 
5.80 
2.70 
1.56 
0.90 
0.37 
0.00 



Note.— Azimuths observed with erroneous declination, or co-latitude may be corrected by means of this 
table by observing that for the line of colhmation set too high, the azimuth of any line from the south point in 
the direction of S. W. N. E. is found too small in the forenoon and too large in the afternoon by the tabular 
amounts for each minute of error in the altitude of the line of sight. The reverse is true for the line set too 
low. 

CORRECTION FOR REFRACTION. 

This correction is applied to the declination of the sun, and is equal to the 
refraction-correction of the sun's observed altitude multiplied by the cosine of the 
angle which the sun makes between the declination-circle and the vertical. 

In order to reduce the refraction correction to the simplest possible form, we 
have added a table showing the refraction for every day of the year, at different 
hours, for latitude 40°, in 5-day periods. 

THE PREPARATION OF THE DECLINATION SETTINGS FOR A DAY'S 

WORK. 

The Solar Ephemeris gives the declination of the sun for the given day, for 
Greenwich mean noon. Since all points in America are west of Greenwich, by 5, 6, 
7 or 8 hours, the declination found in the epherneris is the declination at the given 
place at 7, 6, 5 or 4 o'clock a. m., of the same date, according as the place lies in 
the "Eastern," " Central," " Mountain " or " Western Time " belts respectively. 

The appended, termed "Refraction Correction," gives the correction to be 
made to the declination, for refraction, for any point whose latitude is 40°. If the 
latitude is more or less than 40°, these corrections are to be multiplied by the cor- 
responding coefficients given in the table of " Latitude Coefficients." Thus the 



This table just precedes the "Refraction Correction " table, see following pages. 



THE A. LIETZ COMPANY, 



107 



refraction corrections in latitude 30° are 65 hundredths, and those of 50°, 142 hun- 
dredths of the corresponding ones in latitude 40°. There is a slight error in the use 
of these latitude coefficients, but the maximum error will not amount to over 15", 
except when the sun is very near the horizon, and then any refraction becomes very 
uncertain. All refraction tables are made out for the mean, or average, refraction, 
whereas the actual refraction at any particular time and place may be not more than 
one-half, or as much as twice the mean refraction, with small altitudes. The errors 
made in the use of these latitude coefficients are, therefore, very small as compared 
with the errors resulting from the use of the mean, rather than unknown actual 
refraction which affects any given observation. 

Example I. 

Let it be required to prepare a table of declinations for a point whose latitude 
is 38° 30', and which lies in the " Central Time " belt, for April 5, 1890. 

Since the time is 6 hours earlier than that at Greenwich, the declination given 
in the ephemeris of the Nautical Almanac is the declination here at 6 a. m. of same 
date. This is found to be -f- 6° 9' 57". To this must be added the hourly change, 
which is also plus, and equal to 56".83. The latitude coefficient is 0.94, and the 
refraction corrections which must be multiplied by 0.94 are found in our table for 
April 5th, as follows : 

1st hour 0' 39" X 0.94 = 0' 37" 

2d " 0' 44" X 0.94 = 0' 41" 

3d " 0' 54" X 0.94 = 0' 51" 

4th " V 14" X 0.94 = V 10" 

5th " 2' 08" X 0.94 = 2' 00" 

The same corrections apply to the 4th, 5th, 6th, 7th and 8th of April, but they 
are strictly exact for the middle day of the 5-day period corresponding to that set 
of hourly corrections only. For the extreme days of any such period an interpo- 
lation can be made between the adjacent hourly corrections, if desired. 

The following table may now be made out: 

Declination Settings for April 5, 1890, Lat. 38° 80' , Central Time. 



Hour. 


Declination 


Ref. Cor. 


Setting. 


Hour. 


Declination. 


Ref. Cor. 


Setting. 


7 


4-6° 10' 54" 


+2' 00" 


6° 12' 54" 


1 


6° 16' 35" 


+ 37" 


6°17'12" 


S 


6 11 51 


-fi 10 


6 13 01 


2 


6 17 31 


+ 41 


6 18 12 


9 


6 12 47 


+ 51 


6 13 38 


3 


6 18 28 


+ 51 


6 19 19 


10 


6 13 44 


+ 41 


6 14 25 


4 


6 19 25 


4-rio" 


6 20 35 


11 


6 14 41 


+ 37 


6 15 18 


5 


6 20 22 


4-2 00 


6 22 22 



Example II. 

Let it be required to prepare a declination table for a point in Lat. 45°, in the 
"Eastern Time" belt, for October 10, 1890. 

The time now is 5 hours earlier than that of Greenwich, hence the declination 
given in the ephemeris for Greenwich mean noon is the declination at our point at 



108 



MODERN SURVEYING INSTRUMENTS. 



7 a. m. The declination found is —6° 43' 56", and the hourly change is — 56".8'; 
Our latitude coefficient is 1.20. 
The table then becomes : 

Declination Settings for October 10, 1890, Lett. Jf,5°, Eastern Time. 



Hour 


Declination. 


Ref. Cor. 


Settings. 


Hour 


Declination. 


fief. Cor. 


Settings. 


7 


—6° 43' 56" 


+ 5' 35' 


-6° 38' 21" 


1 


—6° 49' 


37" 


4 V 16" 


— 6°48'21" 


8 


—6 44 53 


-f 2 31 


—6 42 22 


2 


—6 50 


34 


4 1 24 


—6 49 10 


9 


—6 45 50 


+ 1 44 


—6 44 06 


3 


-6 51 


31 


4 1 44 


-6 49 47 


10 


—6 46 47 


4- 1 24 


—6 45 23 


4 


—6 52 


28 


4 2 31 


—6 49 57 


11 


—6 47 44 


+ 1 16 


:— 6 46 28 


5 


—6 53 


25 


4- 5 35 


—6 47 50 



If the date be between June 20, and September 20, the declination is positive, 
and the hourly change negative; while, if it be between December 20, and March 20, 
the declination is negative and the hourly change positive. The refraction correc- 
tion is always positive — that is, always increases numerically the north declina- 
tions, and diminishes numerically the south declinations. 

By using standard time instead of local time, a slight error is made, but the 
maximum value of this error is found at those points where the standard time 
differs from the local time by one-half hour, and in the spring and fall when the 
declination is changing rapidly. The greatest error, then, is less than 30", and 
this is smaller than can be set off on the vertical circle or declination arc. Even 
this error can be avoided by using the true difference of time from Greenwich in 
place of the standard meridian time. 

THE SAEGMULLER SOLAR ATTACHMENT WHEN USED AS A VERTICAL 
SIGHTING TELESCOPE. 

Although this attachment is familiar to every engineer, it is only quite recently 
that it has been recognized as the best Vertical Sighting Telescope which can easily 
be attached to the ordinary transit, and which will give accurate results. 

It is readily seen that the construction of the attachment allows the small tele- 
scope to be placed in a vertical position, and when so placed, as represented in our 
illustrations of transits with solar attachments, it fulfils every requirement of an 
instrument designed for vertical as well as oblique sighting in mining work. 

In order to use the solar for this purpose, proceed as follows: 

See that the transit is in perfect adjustment. Point both telescopes horizontal 
and see that the Solar points as much above the transit telescope as equals the dis- 
tance between their axes. When this is the case the lines of collimation of both 
telescopes are parallel. Now turn the transit telescope 90°, as shown by the vertical 
circle, taking care not to disturb the relative position of the solar telescope and 
that of the transit, and both will point vertically downwards. 

As the standards of the Solar are high enough to allow the small telescope to 
clear the plates, it is evident that the solar telescope now points accurately to the 
Nadir. 

The same modus operandi holds good when it is desired to obtain an oblique 
sight, as it is only necessary to set off the desired slope on the vertical circle, after 
having both telescopes parallel. 



THE A. LIETZ COMPANY. 



109 



For very accurate work it is desirable to make the observations in two positions 
by reversal. By taking the mean of the two sets of observations, instrumental errors 
are eliminated. 

In order to make the Saegmiiller Solar Attachment as efficient as possible for 
the above purpose, the size of the telescope has been increased, giving it ample 
power to locate a point with great precision. 



TABLE OF LATITUDE COEFFICIENTS, 

To be Used in Connection with the Refraction Correction Tables for 
Latitude 40°. (See the following pages.) 



Lat. 


COEFF. 


Lat. 


t 

COEFF. 


Lat. 


COEFF. 


15° 


.30 


31° 


.68 


47° 


1.29 


1(3 


.32 


32 


.71 


48 


1.33 


17 


.34 


33 


.75 


49 


1.38 


18 


.36 


34 


.78 


50 


1.42 


19 


.38 


35 


.82 


51 


1.47 


20 


.40 


36 


.85 


52 


1.53 


21 


.42 


37 


.89 


53 


1.58 


22 


.44 


38 


.92 


54 


1.64 


•23 


.46 


39 


.96 


55 


1.70 


24 


.48 


40 


1.00 


56 


1.76 


25 


.50 


41 


1.04 


57 


1.82 


26 


.53 


42 


1.08 


58 


1.88 


27 


.56 


43 


1.12 


59 


1.94 


28 


.59 


44 


1.16 


60 


2.00 


29 


.62 


45 


1 . 20 






30 


.65 


46 


1.24 







110 



MODERN SURVEYING INSTRUMENTS. 



REFRACTION CORRECTION*. 

Latitude 40°. 

























Refrac- 




Refraction 




Refraction 




Refraction 




Refraction 




Refraction 




tion Cor- 


Jam 


Correction 


Feb. 


Correction 


Mar. 


Correction 


Apr. 


Correction 


May. 


Correction 


June 


rection 




Lat. 40 cleg. 





Lat 40deg. 




Lat. 40 cleg. 




Lat. 40 cleg. 




Lat. 40 deg, 




Lat. 
40 deg. 




h. ' " 






h. ' " 




k.' 




h. ' " 


h.' " 


1 


1 1.58 


1 




1 


1 1.03 


1 


3 0.57 


1 


1 0.28 


1 


5 1.11 


a 


2 2.16 


2 




2 


2 1.10 


2 


4 1.19 




2 0.32 


2 






3 3.04 




h. ' " 


3 1.27 


3 


5 2.18 


2 


3 0.39 






3 


4 6.23 


3 


1 1.26 


3 


4 2.06 








4 0.55 


3 


1 0.19 






4 


2 1.37 


4 


5 4.39 


4 


1 0.39 


3 


5 1.30 


4 


2 0.23 


4 


1 1.54 


5 






5 


2 0.44 






5 


3 0.30 


5 


2 2.11 


6 


3 2.04 


5 


1 0.59 


6 


3 0.54 


4 


1 0.26 


6 


4 0.43 


6 


/ 


4 3.21 


6 


2 1.06 


7 


4 1.14 


5 


2 0.30 


7 


5 1.10 


- 


3 2.59 






i 


3 1.21 


8 


5 2.08 


6 


3 0.37 






8 


4 6.01 


8 


1 1.21 


8 


4 1.56 






7 


4 0.53 


8 


1 0.18 






9 


2 1.31 


9 


5 4.04 


9 


1 0.36 


8 


5 1.26 


9 


2 22 


9 


1 1.5.1 


10 






10 


2 0.41 






10 


3 0.29 


10 


11 


3 1.56 


10 


1 0.55 


11 


3 0.51 


9 


1 0.25 


11 


4 0.43 


11 


2 2.07 


12 


4 3.04 


11 


2 1.02 


12 


4 1.10 


10 


2 0.29 


12 


5 1.09 


12 


3 2.51 






12 


3 1.15 


J 13 


5 1.58 


11 


3 0.36 






13 


4 5.40 


13 


1 1.16 


13 


4 1.47 






12 


4 0.51 


13 


1 0.1S 






14 


2 1.25 : 


14 


5 3.34 


14 


1 0.34 


13 


5 1.22 


14 


2 22 


14 


1 1.46 


15 


3 1.48 






15 


2 0.38 






15 


3 0.29 


15 


16 


4 2.47 ; 


15 


1 0.52 


16 


3 0.48 


14 


1 0.23 


16 


4 0.42 


16 


2 2.01 


17 


5 S.39 


16 


2 0.58 


J7 


4 1.06 


15 


2 0.27 


17 


5 1.0S 


17 


3 2.40 






17 


3 1.10 


18 


5 1.49 


16 


3 0.34 






18 


4 5.00 


18 


1 1.12 


18 


4 1.39 






17 


4 0.49 


18 


1 0.18 






19 


2 1.20 


19 


5 3.08 


19 


1 0.32 


18 


5 1.18 


19 


2 0.22 


19 


1 1.42 


20 


3 1.40 






20 


2 0.36 


19 
20 
21 
90 


1 0.22 

2 0.26 

3 0.33 

4 0.47 

5 1.15 


20 


3 0.29 


20 


21 


4 2.31 


20 


1 0.48 


21 


3 0.45 


21 


4 0.42 


21 


2 1.56 


22 


5 6.49 


21 


2 0.54 i 


22 


4 1.02 


22 


5 1.0S 


22 


3 2.31 






| 22 


3 1.05 


23 


5 1.42 






23 


4 4.35 


23 


1 1.07 


23 


4 1.32 






23 


23 


1 0.18 






24 


2 1.15 


24 


5 2.51 


24 


1 0.30 


24 


2 0.22 


24 


1 1.37 


25 


3 1.33 






25 


2 0.34 


24 


1 0.21 


25 


3 0.29 


25 


2 1.58 


26 


4 2.18 


25 


1 0.45 


26 


3 0.42 


25 


2 0.25 


26 


4 0.42 


26 


27 


5 5.29 


26 


2 0.50 


27 


4 0.58 


26 


3 0.32 


27 


5 1.08 


27 


3 2.22 






27 


3 1.01 


28 


5 1.36 


27 


4 0.46 






28 


4 4.07 


28 




28 


4 1.25 






28 


5 1.13 


28 


1 0.18 






29 




29 


5 2.34 


29 


1 0.28 






29 


2 0.22 


29 


1 1.32 










30 


2 0.32 


29 


1 0.20 ] 


3 0.29 


30 


2 1.44 






30 


1 0.42 








2 0.24 I 


30 


4 0.43 


3 2.13 






31 


2 0.47 






30 


3 0.31 i 






31 


4 3.41 














31 


4 0.44 1 

5 1.11 | 







♦These corrections are strictly correct for the middle day only of the rive-day period, for the hours as shown, 
tn the case of extreme days of the period, an interpolation may be made. 



THE A. LIETZ COMPANY. 



Ill 



REFRACTION CORRECTION. 

Latitude 40°. 





























Refrac- 




Refraction 




Refraction 




Refraction 




Refraction 




Refraction 




tion Cor- 


July 


Correction 


Aug. 


Correction 


Sept. 


Correction 


Oct. 


Correction 


Nov. 


Correction 


Dec. 


rection 




Lat. 40 deg. 




Lat. 40 deg. 




Lat. 40 deg. 




Lat. 40 deg. 




Lat. 40 deg. 




Lat. 
40 deg. 




h. ' " 








h. ' " 




h. 


, » 




h. 


, n 




h. ' " 


1 


5 1.09 


1 




1 


1 0.39 


1 


1 


0.59 


1 


2 


1.37 


1 


1 1.54 


2 








2 


2 0.44 


2 


2 


1.06 


2 


3 


2.04 


2 


2 2.11 








h. ' " 


3 


3 0.54 


3 


3 


1.21 


3 


4 


3.21 


3 


3 2.59 


3 


1 0.19 


2 


1 0.26 


4 


4 1.14 


4 


4 


1.56 


4 


5 


13.57 


4 6.01 


4 


2 0.23 


3 


2 0.30 


5 


5 2.08 


5 


5 


4.04 








4 


5 


5 


3 0.30 


. 4 


3 0.37 












5 


1 


1.32 






6 


4 0.43 


5 


4 0.53 


6 


1 0.42 


6 


1 


1.03 


6 


2 


1.44 


5 


1 1.58 


7 


5 1.10 


6 


5 1.26 


7 


2 0.47 


7 


2 


1.10 


7 


3 


2.13 


6 


2 2.16 










8 


3 0.57 


8 


3 


1.27 


8 


4 


3.41 


7 


3 3.04 


8 


1 0.20 


7 


1 0.28 


9 


4 1.19 


9 


4 


2.06 


9 


5 




8 


4 6.23 


9 


2 0.24 


8 


2 0.32 


10 


5 2.18 


10 


5 


4.39 








9 


5 


10 


3 0.31 


9 


3 0.39 












10 


1 


1.37 






11 


4 0.44 


10 


4 0.55 


11 


1 0.45 


11 


1 


1.07 


11 


2 


1.50 


10 


1 2.00 


12 


5 1.11 


11 


5 1.30 


12 


2 0.50 


12 


2 


1.15 


12 


3 


2.22 


11 


2 2.19 










13 


3 1.01 


13 


3 


1.33 


13 


4 


4.07 


12 


3 3.09 


13 


1 0.21 


12 


1 0.30 


14 


4 1.25 


14 


4 


2.18 


14 


5 




13 


4 6.38 


14 


2 0.25 


13 


2 0.34 


15 


5 2.34 


15 


5 


5.39 








14 


5 


15 


3 0.32 


14 


3 0.42 












15 


1 


1.42 






16 


4 0.46 


15 


4 0.58 


16 


1 0.48 


16 


1 


1.12 


16 


2 


1.56 


15 


1 2.01 


17 


5 1.13 


16 


5 1.36 


17 


2 0.54 


17 


2 


1.20 


17 


3 


2.31 


16 


2 2.20 










18 


3 1.05 


18 


3 


1.40 


18 


4 


4.35 


17 


3 3.11 


18 


1 0.22 


17 


1 0.32 


19 


4 1.32 


19 


4 


2.31 


19 


5 




18 


4 6.47 


19 
20 


2 0.26 

3 0.33 


18 
19 


2 0.36 

3 0.45 


20 


5 2.51 


20 


5 


6.29 


20 


1 


1.46 


19 


5 


21 


4 0.47 


20 


4 1.02 


21 


1 0.52 


21 


1 


1.16 


21 


2 


2.01 


20 


1 2.01 


22 


5 1.15 


21 


5 1.42 


22 


2 0.58 


22 


2 


1.25 


22 


3 


2.40 


21 


2 2.20 










23 


3 1.10 


23 


3 


1.48 


23 


4 


4.59 


22 


3 3.11 


23 


1 0.23 


22 


1 0.34 


24 


4 1.39 


24 


4 


2.47 


24 


5 




23 


4 6.49 


24 


2 0.27 


23 


2 0.38 


25 


5 3.08 


25 


5 


8.39 








24 


5 


25 


3 0.34 


24 


3 0.48 












25 


1 


1.50 






26 


4 0.49 


25 


4 1.06 


26 


1 0.55 


26 


1 


1.21 


26 


2 


2.06 


25 


1 2.00 


27 


5 1.18 


26 


5 1.49 


27 


2 1.02 


27 


2 


1.31 


27 


3 


2.49 


26 


2 2.19 










28 


3 1.15 


28 


3 


1.56 


28 


4 


5.33 


27 


3 3.09 


28 


1 0.25 


27 


1 0.36 


29 


4 1.47 


29 


4 


3.04 


29 


5 




28 


4 6.43 


29 


2 0.29 


28 


2 0.41 


30 


5 3.34 


30 


5 


11.01 








29 


5 


3 0.36 


29 


3 0.51 












30 










30 


4 0.51 


30 


4 1.10 








1 


1.26 








30 




31 


5 1.22 


31 


5 1.58 






31 












31 





PART IY. 
Illustrated Catalogue and Price List 

OF 

MODERN 

ENGINEER'S and SURVEYOR'S INSTRUMENTS, 

Guaranteed in every Detail. 



MADE BY 



THE A. LIETZ COMPANY, 

Manufacturers of Scientific Instruments, 
No. 422 Sacramento Street, 

San Francisco, 
California. 



INTRODUCTION TO PART IV. 



r I ^HE following illustrations show the principal articles man- 
-*- ufactured by this Company, being in the case of this cata- 
logue almost exclusively confined to instruments required by 
the civil, mining, irrigation, hydraulic and military engineer, 
for making accurate measurements and surveys for any purpose 
whatever. 

Of the surveying instruments each illustration, or plate, is 
complete within itself. Every part is carefully noted upon the 
back, together with the price, and a general description in a 
condensed form. The additional accessories that may be had 
in each instance, are also enumerated and their prices given. 
It is well, however, that the engineer who is looking for an 
article, should consult the preceding Part II of this Manual, 
wherein every detail is carefully described and extensively dis- 
cussed. If pains are taken to look this over, the reader will 
obtain all the information that could possibly be given him in 
the shop. 

Every article has been numbered, and by these numbers 
our customers may order, without going into a minute descrip- 
tion of the articles wanted. For example: 

11 Send me transit Xo. 4, with the following extras " 

is all that is required to designate to us exactly what is desired 
by our patron. 

With the detailed information on its reverse side, every 
plate becomes a complete price list of the particular instrument 
illustrated. Every effort has been made to make this part of 
the book as intelligible as possible, without the necessity of 
-••arching over numerous pages to gather information. 



Although we shall make any instrument of precision called 
for, we desire to state clearly that we have made a particular 
specialty of engineer's and surveyor's instruments, because 
there is for them alone a demand at the present time, and for 
this reason our shop facilities have been especially designed 
and improved for the manufacture of these articles. 

If instruments for a more scientific purpose are wanted, for 
astronomical or geodetic work, for instance, we can either make 
them on a special order, or we can import them for our customer, 
having made arrangements in Europe, which enables us to sell 
such instruments as cheaply as any one in the United States. 
For institutions of learning we import without payment of duty. 

We have added a number of illustrations of imported astro- 
nomical and geodetic instruments, which are marked with a f, 
to distinguish them from our own make. The prices are gen- 
erally given, but where not so given, or in case particular spe- 
cialties are wanted that are not shown, we shall be glad to fur- 
nish an estimate of the probable cost. 

In all our manufacture the prices have been marked com- 
mensurate with the quality of the work, and no deductions can 
be made from our price list, which agrees in all its quotations 
with those of our best Eastern firms. 

We furnish a first-class article at a fair price, and all goods 
stand upon their individual merit. It is our object to introduce 
the Lietz instrument to the profession generally, and to prove 
all the claims that we are making for it, and with our earnest 
effort and encouragement we feel confident of future success. 

The A. Lietz Company. 



Engineer's and Surveyor's Transits, 

Nos. 1 to 4. 

These are elegant instruments, absolutely accurate in all 
working parts, designed for land surveying and engineering 
work of a high character. 

The general dimensions are given on the back of each il- 
lustration, as well as the price, and the extras that may be had 
upon application. By carefully inspecting the plates, the price 
list and the enumerated extras, the purchaser is enabled to 
choose the article and any desired accessory, and make an esti- 
mate of its cost. 

We make each style in hard aluminium, which increases 
the price 15%. 

The horizontal circle is graduated to read to either 60, 30 or 
20 seconds, two double verniers being provided, placed so as to, 
afford a reading without stepping aside. The vertical arc or 
circle is graduated to read to 60 or 30 seconds. Every instru- 
ment has long compound centers, shifting plates on tripod 
head, with new improved coupling. The telescope possesses 
definition, light and power in a high degree. It has Jena glass 
lenses, achromatic objective and eye-piece. Erect vision. 
The telescope is reversible and evenly balanced, provided with 
slide protector, and screw motion for focusing cross-hairs. The 
standards are cloth-finished. The case has leathern straps, rub- 
ber cushions, and contains all the usual accessories. For a 
minute description of every detail, see Part II of the Manual. 



Part IV Plate I. 




The A. Lietz Company, 
makers, 

San Francisco, Cal. 



No. 1. 

PLAIN TRANSIT. 

Price, $185. OO. 

£flS^" For details and extras, see the back of this plate. 



No. 1. 

Dimensions and Weight. 

Horizontal Circle (measured to the edge of graduation), 6J inches diam. 

Compass Needle, . .... 

Object Glass, ....... 

Telescope, . . . . . 

Magnifying power, ..... 

Weight of instrument, .... 

" tripod, ..... 

" box, ..... 

Weight of this instrument if made of hard aluminium, 
The price of this instrument as shown is ... 

And if made of hard aluminium, 15^ are added. 



n 


long. 


n 


" diam. 


11 


long. 




24 


15 


lbs. 


81 


" 


8 


" 


7£ 


" 




$185.00 



The Extras, for which additional charge is made, are as follows: 

Solid Silver Graduations: 

On horizontal circle, ...... §10.00 

On TTfirtirml nm nv ainolci J . 00 

Verniers, reading to 30" on horizontal circle, .... 10.00 

20" " " .... 20.00 

(■y»^iiiittwi' ■lUnuhiiiont. ...... 5 . 00 

Stadia hairs, fixed, . . . . . . .3.00 

" adjustable, . . . . * . 10.00 

Variation plate, . . . . . . . .10.00 

Arrangement for offsetting right angles, . . . . 5.00 

Striding level to axis of telescope, . . . .20.00 

Constructed with three leveling screws on base plate, instead of four. 10.00 

Three leveling-serew shifting center, . . . .5.00 

Prism, attachable to eye-piece, . . 8.00 

Extra extension tripod, . . . . .15.00 

Protection bag, . . . 1.00 

Bottle of fine watch oil, ...... .25 

anLgmullui Oulai AlULlimuiit : 

Of lud mulal, ... 

" aluminium. 



Part IV, Plate II. 




The A. L/Ietz Company, 
Makers, 

% San Francisco, Cal. 



No. 2. 

TRANSIT, WITH LEVEL TO TELESCOPE. 

Price, $215.00. 

For details and extras, see the back of this plate. 



No. 2. 

Dimensions and Weight. 

Horizontal Circle (measured to the edge of graduation), . 6^ inches diam. 

Compass Needle, ...... 4J- " long. 

Object Glass, . . . . . 1-J " diam. 

Telescope, . . . . . 11 " long. 

Magnifying power, . . . . .24 

Weight of instrument, .... 15 lbs. 

" tripod, . . . . . 8| " 

box, ..... 8 " 

Weight of this instrument if made of hard aluminium, 11 " 

The price of this instrument as shown is . . . .$215.00 

And if made of hard aluminium, 15$ added. 



The Extras, for which additional charge is made, are as follows: 

Solid Silver Graduations: 

On horizontal circle, . . . . . . $10.00 

Verniers, reading to 30" on horizontal circle, . . . 10.00 
20" " .... 20.00 

Gradienter Attachment, . . . . . 5.00 

Stadia hairs, fixed, . . . . . . .3.00 

" adjustable, . . . . . 10.00 

Variation plate, . . . . . . .10.00 

Arrangement for offsetting right angles, . . . . 5.00 

Striding level to axis of telescope, . . . . . .20.00 

Constructed with three leveling screws on base plate, instead of four, 10.00 

Three leveling-screw shifting center, . . .5.00 

Prism, attachable to eye-piece, ..... 8.00 

Extra extension tripod, . . . . . . 15.00 

Protection bag, . . . 1.00 

Bottle of fine watch oil, . . . . . .25 



Part IV, Plate III. 




f he A. Ltetz Company, 

Makers, 

San Francisco. 



No. 3. 

COMPLETE ENGINEERS' TRANSIT, 

With Vertical, Arc. 
Price, $230.00. 

For details and extras see the back of this plate. 



No. 3. 



Dimensions and Weight. 



Horizontal Circle (measured to edge of graduation), 

Vertical Arc (measured to edge of graduation), 

Compass Needle, ...... 

Object Glass, ...... 

Telescope, ....... 

Magnifying power, ..... 

Weight of instrument, ..... 

" tripod, ..... 

" box, ...... 

Weight of this instrument if made of hard aluminium, 
The price of this instrument as shown is 

And if made of hard aluminium, 15 <> added. 



6J inches diam. 


5 " 


" 


H " 


long. 


H ' 


diam. 


l 


long. 


24 




15 lbs. 




8^ •' 





S230.00 



The Extras, for which additional charge is made, are as follows: 



Solid Silver Graduations: 

On horizontal circle, ..... 

On vertical arc, ...... 

Verniers, reading to 30" on horizontal circle, 

20" " ... 

Gradienter Attachment, ..... 

Stadia hairs, fixed, ....... 

" " adjustable, ..... 

Variation plate. ....... 

Arrangement for offsetting right angles, 

Striding level to axis of telescope, .... 

Constructed with three leveling screws on base plate, instead of four, 
Three leveling-screw shifting center, .... 

Prism, attachable to eye-piece, ... 

Extra extension tripod, ....... 

Protection bag, ...... 

Bottle of fine watch oil, ...... 

Saegmuller Solar Attachment: 

Of red metal. .... 

aluminium, ....... 



no. 00 

5.00 
10.00 
20.00 

5.00 

3.00 
10.00 
10.00 

5. CO 
20.00 
10.00 

5 . 00 

8.00 
15.00 

1.00 

50.00 

60.00 



Part IV, Plate IV. 




ruE A. I.ietz Company, 

Makers, 

San Francisco, Cal. 



No.4. 
COMPLETE ENGINEERS' TRANSIT, 

With Full Vertical Circle. 
Price, $235. OO. 
For details and extras see the back of this plate. 



No. 4. 



Dimensions and Weight. 



Horizontal Circle (measured to edge of graduation), 

Vertical Circle (measured to edge of graduation), 

Compass Needle, ...... 

Object Glass, ...... 

Telescope, ....... 

Magnifying power, ..... 

Weight of instrument, ..... 

" tripod, . ... 

" .box, ...... 

Weight of this instrument if made of hard aluminium, 
The price of this instrument as shown is 

And if made of hard aluminium, 15$ added. 



6J inches diam 


5 - 


" 


" 


41 


" 


long 


H 


: < 


diam 


11 


24 


long 


15 


lbs. 




8| 


" 





7! 



|235 . 00 



The Extras, for which additional charge is made, are as follows 



Solid Silver Graduations: 

On horizontal circle, ..... 

On vertical circle, ...... 

Verniers, reading to 30" on horizontal circle, 

20" " ... 

Gradienter Attachment, ..... 

Stadia hairs, fixed, ....... 

" " adjustable, ..... 

Variation plate, ....... 

Arrangement for offsetting right angles, 

Striding level to axis of telescope, . . 

Constructed with three leveling screws on base plate, instead of four. 

Three levelmg-screw shifting center, .... 

Prism, attachable to eye-piece, ...... 

Extra extension tripod, ...... 

Protection bag, ...... 

Bottle of fine watch oil, ...... 

Saegm idler Solar Attachment: 

Of red metal, . . . . ... 

" aluminium, ....... 



110.00 


5.00 


10.00 


20.00 


5.00 


3.00 


10.00 


10.00 


5.00 


20.00 


10.00 


5.00 


8.00 


' 15.00 


1.00 


.25 


50.00 


60.00 



Part IV, Plate V. 




The A. Lietz Company 

Makers, 

San Francisco, Cai.. 



No. 5. 

COMPLETE TRANSIT -THEODOLITE, 

For Highest Grade Engineering Work. 
For particulars and price, see the back of this plate. 



No. 5. 

TRANSIT - THEODOLITE. 

This is an instrument of very superior construction. 

The standards upon which the telescope rests are cast in one U-shaped piece, thus affording more strength 
than the ordinary form. 

The telescope is reversible in position, as well as exchangeable in its bearings, which are provided with dust- 
caps and screws, to give them the proper friction. The telescope is either erect or inverting. For reasons already 
set forth, the inverting form should be given the preference. The telescope possesses the finest lenses and opti- 
cal accessories. It has a slide protector and is provided with a sun-shade. The cross hairs are focused by a screw 
motion of the eye-piece. 

All the graduations are on solid silver. The horizontal circle reads to either 30, 20 or 10 seconds, by two op- 
posite verniers, near the line of collimation, which are supplied with two attached reading glasses, if desired. 
The vertical arc or circle is graduated to read to 30 seconds. 

The instrument is furnished with either three or four leveling screws, that operate through a slotted star, as 
already described in the case of the other instruments. 

A shifting center is provided, with extra cover plate to protect it from dust. 

The U-shaped casting, constituting the support for the telescope, may be either in cloth-finish, or in bright 
lacquer like the rest of the instrument. The metal finish may be had of any desired color. 

The new Lietz tripod coupling is furnished without extra charge. 

The case contains all the usual accessories, such as plumb bob, screw driver, adjusting pins, etc. 

Dimensions and Weight. 

Horizontal Circle (measured to edge of graduation), . 6£ inches diam. 

Vertical Arc or Circle (measured to edge of graduation), . 5 " " 

Compass Needle (in bos on plate), . . . 3| " long. 

Telescope, . . . . . . 11 " " 

Object Glass, . . . . . . 1^ " diam. 

Magnifying power, ..... 24 

Weight of instrument, . . . . .16 lbs. 

" tripod, . . . . . 8% " 

" box, . . . . . . 8 " 

If made of aluminium, the weight of the instrument is reduced 50$. 

The price of the plain transit-theodolite (without a level, clamp and arc to telescope) 
is |240.00, and if made of hard aluminium 15$ are added. 

The Extras, which make the instrument more or less complete, 
are as follows: 

Verniers reading to 20" on a 6J inch horizontal circle, . . §10.00 

" 10" " 7 " " " . 35.00 

A 5-inch vertical arc, reading to minutes, . . .20.00 

A 5-inch full vertical circle, reading to minutes, . . . 25.00 

" " " with opposite double verniers, reading to minutes, 50.00 

Two vernier microscopes, ....... 15.00 

Long ground level to telescope, with compound clamp and tangent screw, 

telescope reversible, and supplied with gradienter attachment, . 40.00 

Striding Level, . . . . . . .20.00 

Stadia Hairs, fixed, ....... 3.00 

adjustable, . . . . . .10.00 

Box Needle, on plate, . . . . . . . 20.00 

Constructed with three leveling screws on base plate, instead of four, 10.00 

Three leveling screw shifting center, . . . 5.00 

Prism attachable to eye-piece, • . . . . . .8.00 

Protection bag, . . . 1.00 

Bottle of fine watch oil, ...... .25 

Saegmiiller solar attachment, of red metal, .... 50.00 

" " " of aluminium, .... 60.00 



Part IV, Plate VI. 




A. I,ietz Company, 

Makers, 
San Francisco. Cal. 



No. 9. 
COMPLETE MOUNTAIN AND MINING TRANSIT. 

No. 6 is the Plain Mountain and Mining Transit. 
No. 7 the same as No. 6 with telescope level. 
No. 8 the same as No. 7 with a vertical arc. 

For details, prices and extras, see the back of this plate. 



SMALL MOUNTAIN AND MINING TRANSIT. 
No. 6. 
THE PLAIN TRANSIT. 
This is a beautiful instrument, made to correspond in every way with No. 1, ex- 
cept in size and weight. It is a superior and reliable article for general land sur- 
veying, and particularly for mining purposes. 

Dimensions, Nos. 6 to 9. 
Horizontal Circle (measured to edge of graduation), 
Vertical Arc or Circle (measured to edge of graduation), 
Compass Needle, ..... 

Object Glass, ...... 

Telescope, ...... 

Magnifying power, .... 

Weight of instrument, 

tripod, .... 

" box, .... 

Weight of this instrument, if made of hard aluminium, 



5 inches diam. 
4 

" long. 
" diam. 
long. 
18 
lbs. 



41 

1 



6 
6 



The price of the plain transit, No. 6, is 
With level to telescope and tangential movement, No. 7. 
With Vertical arc in addition, No. 8, ... 

With full vertical circle, No. 9, 

And if made of hard aluminium. 15 v are added. 



§180.00 
210.00 
225.00 
230.00 



The Extras, for which additional charge is made, are as follows: 
Solid Silver Graduations: 

On horizontal circle, •. . . . . . £10.00 

On vertical arc or circle . . . . . .5.00 

Gradienter Attachment, . . . . . . 5.00 

Stadia hairs, fixed, . . . . . .3.00 

" adjustable, ...... 10.00 

Variation Plate, . . . . . . . .10.00 

Arrangement for offsetting right angles, . . . . ' 5.00 

Striding level to axis of telescope, ..... 20.00 

Constructed with three leveling screws on base-plate, instead of four, 10.00 

Three leveling-screw shifting center, . . . . . 5.00 

Prism attachable to eye-piece, . . . . 8.00 

Half-length tripod, . . . . .13.00 

Extra extension tripod, . . . 15.00 

Detachable side telescope, . . . . .35.00 

Lamp for mining engineering, of brass, with ground lens, . 7.00 

Reflector, for illuminating cross hairs, . . .4.00 

Plummet lamp, . . . . 10.00 

Large plumb-bob, weight 4 lbs., for use in shafts, . . 5.00 

Protection bag, . . . . . . . 1.00 

Bottle of fine watch oil, . . . . . . .25 

Saegniuller solar attachment: 

Of red metal, . 50.00 

Of aluminium, . . . .60.00 



No. 10. Mining Transit. 

The same dimensions as in Nos. 1 to 4. Graduations on 
solid silver; verniers, reading to minutes, provided with glass 
shades; 5-inch full vertical circle; spirit level, clamp and tan- 
gent screw to telescope; extension tripod, etc. Price, $258.00. 
If made of hard aluminium, 15% added. 

No. 1 1 . Mining Transit. 

The same dimensions as in Nos. 6 to 9. Graduations on 
solid silver; verniers, reading to minutes, provided with glass 
shades; 4-inch full vertical circle; spirit level, clamp and tan- 
gent screw to telescope; extension tripod, etc. Price, 1253.00. 
If made of hard aluminum, 15% added. 

It must be apparent that there cannot be any great differ- 
ence in price between a large and a small-sized instrument. 
The workmanship in each is alike, and, if anything, more com- 
plicated and costly in the smaller. The only difference is in 
the quantity of metal used, but as this can not possible amount 
to much in price, it is more than compensated by the additional 
care required in handling the smaller parts. This explanation 
would hardly seem necessary, were it not for the prevailing im- 
pression that all merchantable articles of the same kind should 
be rated by their respective sizes. That this cannot obtain in 
the case of instruments must stand to reason. The price of a 
transit can only be reduced by omitting certain features, or by 
changing it to a simpler construction. For this reason we have 
built a small instrument, in which the double vertical center is 
changed to a single one, which greatly lessens the cost of pro- 
duction. We would call your attention to the following descrip- 
tion of this line of goods, for which we have found a ready 
market on the Pacific Coast. These instruments answer ex- 
ceedingly well for many purposes where great refinement would 
be unnecessary and a waste of time. In stadia topography they 
are not excelled. 



The Lietz Simplified Transit. 

It has been the aim of the Company to build an instrument 
considerably less in cost than the complete field transit or the- 
odolite, that shall suffer nothing in workmanship or in the ac- 
curacy of its individual parts. We have already stated our 
policy: that we will not produce an inferior article in our fac- 
tory. If it be required to reduce the price of an instrument, 
the only means left open to us is to omit certain features, and 
in that way obtain the desired result. 

In a transit instrument certain expensive accessories may 
be left off, that in the ordinary practice are seldom or never re- 
quired. But one of the most costly features is that which gives 
to it the double horizontal motion, we mean the construction of 
the double center, which requires the most refined parts and 
delicate workmanship, if it is to perforin its function accurate- 
ly. Now, by making an instrument with a single center, that 
shall possess a motion around the plate only, we can greatly 
reduce the cost without sacrificing anything in accuracy, or in 
the construction of the other main features. And that is what 
constitutes a simplified transit, an instrument extensively used 
in Europe. It differs in nothing from the others, save in the 
arrangement from the circle plate down to the tripod head. 

Every observation in both planes may be made with all the 
necessary precision required of the ordinary transit, but in 
order to obtain a horizontal angle, the observer must take two 
readings of the plate, one on the object measured from, and the 
other on the object measured to. The difference between the 
two readings is the angle sought. While this may require a 
little more office work, there are many cases when even this 
will not be materially increased. In topographical surveying, 
for instance, where a great many observations are taken from 
one station, what matters it whether we are able to place the 
zero upon any one of the objects? The relative directions of 
all the observed points are known, and they may be plotted in 
the office without reducing them to any particular azimuth, 
since we are able to place our protractor on the drawing, upon 
the starting point with the same reading that the transit gave 
in the field. In that case we may ignore the zero altogether. 




o 




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CO 10 

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CO 
CO 

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CM 



SIMPLIFIED TRANSITS (COMPASSES.) 

No. 12. 

Possessing a single center; horizontal leveling screws, and ball joint movable in 
socket. Xo horizontal plate. Compass needle and graduated compass ring, with 
variation plate. Sensitive plate levels. Cloth finished standards, carrying a fine 
achromatic telescope. The telescope is reversible and accurately balanced. It affords 
ample definition, power and light. May be had with or without stadia hairs. 

The instrument is packed in a handsome case containing a plumb bob, adjusting 
pins and all the usual accessories. 

A light but strong tripod is furnished. 

Dimensions and Weight. 

Compass Needle, 

Telescope, .... 

Vertical Arc, 

Object Glass, 

Magnifying power, 
Weight of instrument, 
" tripod, 

" box, 

The price of this instrument is 

Stadia hairs, 83.00 extra. 



3£ Inc 


hes 


long. 


8 




< 


long. 


-4 




' 


diam. 


1 




18 


" 




7i lbs. 






6 


t ( 






4| 


", 


sso.oo 



No. 13. 

The same as Xo. 12, with a level to the telescope, and clamp and tangential 
movement to telescope axis. 

Price, . . . . . 8105.00 

Stadia hairs, 83.00 extra. 



No. 14. 

The same as Xo. 13. with a vertical arc- graduated to read to miuutes. 
Price, . . . . . 8118.00 

Stadia hairs, 83.00 extra. 



In many different branches of the surveyor's work this in- 
strument will give every satisfaction, since nothing is sacrificed 
in the accuracy of its working parts. The telescope has the 
best lenses, accurately centered and of ample power, and rests 
upon cloth-finished standards. The circle is divided to read 
to minutes, and is free from all eccentricity in its motion. 
The needle is of the best make and may be read with the same 
accuracy as that of any other transit. The leveling is done by 
two pair of opposing leveling screws, mounted horizontally (see 
the appended illustrations), that operate against a ball in a 
socket, admitting of a very accurate adjustment to the proper 
plane indicated by two sensitive plate bubbles. While one lev- 
eling screw is loosened or drawn out, the opposing one is oper- 
ated against the ball until the inclination of the vertical axis is 
nil. This is done with both sets until the plate bubbles remain 
centered for any position in azimuth. The ball may be so held 
between the screws that it becomes perfectly rigid, and the in- 
strument steady. This construction, although not affording 
that absolute rigidity under the more trying circumstances of 
wind and weather, as in the star-shaped casting and foot screw 
arrangement of our other transits, is yet fully up to, and supe- 
rior to many of the various makes that possess the disc instead 
of the star through which the leveling screws operate. 

These simplified instruments are made in different vari- 
eties, containing one or more of the accessories for refined field 
work. 

1st. The compass, without a graduated plate, fit for sur- 
veying by needle courses alone. (See Plate VII, Nos. 12 to 14.) 

The instrument possesses a needle, compass graduation, 
variation plate, two plate levels, and a high, grade telescope 
mounted upon cloth-finished standards. It can be accurately 
centered over a point by means of a plumb-bob, attachable un- 
der the tripod head, upon which this transit compass is mounted 
by means of a screw. Upon the telescope provisions are made 
for receiving the Saegmiiller Solar Attachment, if required, and 
in this wise an instrument is created by far superior to the old- 
fashioned surveyor's compass with metal sights, or to the cum- 
bersome solar compass, with its rough motions and its crude 



means of obtaining approximately the direction of a line. 
These antiquated relics, although costing fully as much, can 
not by any possibility be as reliable. (See Plate IX, No. 18.) 

2d. In the higher class of simplified transits the horizon- 
tal plate is graduated, and a vernier supplied to read to one 
minute in azimuth. This may be called a plain transit of this 
grade. (See Plate VIII, No. 15.) 

3d. The complete simplified transit (No. 17) possesses the 
additional features of a level to the telescope, a vertical arc, 
gradienter screw and stadia hairs. This may be supplemented 
by the Saegmuller Solar Attachment. (See Plate X, No. 19.) 

With this instrument the engineer is able to do very accu- 
rate work in ordinary triangulation, compass surveying, stadia 
measurements and leveling. It is small, light and easy to 
handle. It is readily set over a point in the field, centered and 
leveled up. In observing, the plate is turned until the telescope 
has the direction of the desired mark, when the plate is clamped 
by the screw under it, and the mark bisected by means of the 
tangent screw. The vernier of the horizontal circle is then 
read, after which the clamp may be released, for the instrument 
is now oriented for the measurement of any direction or distance. 

These transits are packed in a neat little case, and are fur- 
nished with a light tripod with round solid legs. 

In the following descriptive list our customers will find that 
the prices quoted are very moderate for these elegant articles. 
We have there given the sizes of the parts, and the accessories 
to each with the cost, so that any one is enabled to choose just 
what he may need and to figure up the expense. 

We claim that in these simplified transits we have -given to 
the profession a cheap instrument, without taking from it any 
of the high qualities of workmanship that every instrument of 
ordinary precision should possess. 

That its zero cannot be placed on an object is no particular 
drawback in many cases of engineering work, as we have al- 
ready explained. 

The adjustments of the simplified transit are in every way 
similar to those of the double motion transit, which have been 
fully discussed in another place. 





CO 






in 



S w | 

£ E 1 



ii 




LO 



SIMPLIFIED TRANSITS. 



No. 15. 

Possessing a single center; horizontal leveling screws operating against a ball in 
a socket. The horizontal plate is graduated to read to minutes by one vernier placed 
near the eye end of the telescope. Compass needle and graduated compass ring, with 
variation plate. Sensitive plate levels. Cloth finished standards, carrying a fine 
achromatic telescope. The telescope is reversible and accurately balanced. It affords 
ample definition, power and light. May be had with or without stadia hairs. 

The instrument is packed in a handsome case containing a plumb bob, adjusting 
pins and all the usual accessories. 

A light but strong tripod is furnished. 



Dimensions and Weight. 

Horizontal Circle, .... 

Vertical Arc, ...... 

Compass Needle, ..... 

Telescope, ..... 

Object Glass, ... 

Magnifying power, . . . . 

Weight of instrument, 

" tripod, . 

" box, .... 

The price of this instrument is . . . 

Stadia hairs, $3.00 extra. 



5 inches diam. 
4 

3J " long. 
8 " 

1 ' diam . 
18 

7f lbs. 

6 " 

4* " 

$105.00 



No. 16. 

The same as No. 15, with a level to the telescope, and clamp and tangential 
movement to telescope axis. 

Price, ..... $130.00 

Stadia hairs, $3.00 extra. 



No. 1 7. (Complete Simplified Transit.) 
The same as No. 16, with a vertical arc graduated to read to minutes. 
Price, . . $143.50 

Stadia hairs, $3.00 extra. 



Part IV, Plate IX. 




The A. Ltetz Company, 
Makers, 
k San Francisco, Cal. 



No. 18. 

COMPOUND MINING AND SOLAR INSTRUMENT. 

Price, $168. 50 

For details, see the back of this plate. 



No. 18. 

COMPOUND MINING AND SOLAR INSTRUMENT. 

This instrument is like No. 1-i. with a Saegmiiller solar attachment. It possesses 
a single center, horizontal leveling screws, operating against a ball in a socket. No 
horizontal plate. Compass needle and graduated compass ring, with variation plate. 
Sensitive plate levels. Cloth finished standards, carrying a fine achromatic tele- 
scope. The telescope is reversible and accurately balanced. It affords ample defi- 
nition, power and light. May be had with or without stadia hairs. 

The solar attachment is screwed into the top of the telescope axis and becomes 
a part of the instrument. It answers all the purposes of a side telescope, as shown 
in the marginal sketch. 

The whole instrument is packed in a handsome case, with a special place for the 
solar attachment, containing a plumb bob, adjusting pins, and all the usual access- 
ories. 

A light but strong tripod is furnished. 

Dimensions and Weight. 

Compass Xeedle, . .... 31 Inches long. 

Telescope, . . . . 8 " " 

Object Glass, . . . . 1 diam. 

Vertical Arc, . . . . . 4 - ; " 

Magnifying power, ...... 18 

Weight of instrument with solar attachment, 8| lbs. 

" tripod, . . . . 6 " 

box, . . . . . U li 

The price of this instrument is ..... 8168.50 

If the solar attachment is made of aluminium, 810.00 extra. 

Stadia Hairs. 83.00 extra. 



Part IV, Plate X. 




The A. Ljetz Company, 

Makers, 

San Francisco, Cal. 



No. 19. 
COMPOUND MINING AND SOLAR INSTRUMENT. 

Price, $193. 50 

For details, see the back of this plate. 



No. 19. 

COMPOUND MINING AND SOLAR INSTRUMENT. 

This instrument is like No. 17, with a Saegmuller solar attachment. It possesses 
a single center, horizontal leveling screws, operating against a ball in a socket. The 
horizontal plate is graduated to read to minutes by one vernier, placed near the eye 
end of the telescope. Compass needle and graduated compass ring, with variation 
plate. Sensitive plate levels. Cloth finished standards, carrying a fine achromatic 
telescope. The telescope is reversible and accurately balanced. It affords ample 
definition, power and light. May be had with or without stadia hairs. 

The solar attachment is screwed into the top of the telescope axis and becomes 
a part of the instrument. It answers all the purposes of a side telescope, as shown 
in the marginal sketch. 

The whole instrument is packed in a handsome case, with a special place for the 
solar attachment, containing a plumb bob, adjusting pins, and all the usual access- 
ories. 

Dimensions and Weight. 

Horizontal Circle, ...... 

Vertical Arc, ....... 

Compass Needle, ...... 

Telescope, ....... 

Object Glass, ...... 

Magnifying power, . . 

Weight of instrument with solar attachment, 

" tripod, ..... 

" box, ..... 

The price of this instrument is .... $193.50 

If the solar attachment is made of aluminium, $10.00 extra. 

Stadia Hairs, $3.00 extra. 



5 Inches diam 


4 


" 


3| " 


long 


8 


" 


1 


diam 


18 




8£ lbs. 




6 " 




4* " 





Part IV, Plate XI. 




No. 20. 

COMPOUND MINING AND SOLAR TRANSIT. 

Price Complete, $318. OO. 

For details, see the back of this plate. 



No. 20. 
COMPOUND MINING AND SOLAR TRANSIT. 

This instrument is like No. 4, -with the Saegmtiller solar attachment. 

It possesses a double center, lower clamp and tangential movement; plate move- 
ment with clamp and tangent screw, and sensitive plate levels; double verniers 
reading to minutes, placed conveniently for reading without stepping from the eye 
end. Compass needle and graduated compass ring, with variation plate. Cloth 
finished standards, carrying an improved telescope. The telescope is reversible and 
evenly balanced; it affords ample definition, power and light; fixed stadia hairs are 
supplied; it has a long level and possesses a clamp and tangential movement; also 
gradienter attachment; a full or half vertical circle reading to minutes. All gradu- 
ations are on solid silver. The instrument has the Lietz tripod coupling, and a 
shifting center. 

The solar attachment is detachable, screws into the top of the telescope axis, 
and becomes a part of the instrument. It answers all the purposes of a side tele- 
scope, as shown in the marginal sketch. 

The whole instrument is packed in a handsome case, with a special place for the 
solar attachment, containing a plumb-bob, adjusting pins and all the usual acces- 
sories. 

Dimensions and Weight. 

Horizontal Circle (measured to edge of graduation), 
Vertical Arc or Circle (measured to edge of graduation), 
Compass Needle, ...... 

Telescope, ....... 

Object Glass, ...... 

Magnifying power, ..... 

Weight of instrument, .... 

" tripod, ..... 

" box, ..... 

Weight of this instrument, if made of hard aluminium, 
The price of this instrument, complete, is 

And if made of hard aluminium, 8368.00. 



6J inches diam 


5 


(( 


" 


H 


«• 


long 


11 


(i 


" 


14 


24 


diam 


16 


lbs. 




Si 


1 1 





$318.00 



The Extras, for which additional charge is made, are as fol 

Verniers reading to 30" on horizontal circle, 

" 20" " "... 

Adjustable Stadia Hairs, ..... 

Arrangement for offsetting right angles, 

Striding level to axis of telescope, .... 

Constructed with three leveling screws on base-plate, instead of four, 
Three leveling-screw shifting center, .... 

Prism attachable to eye-piece, .... 

Extra extension tripod, ...... 

Half-length tripod, ...... 

Detachable side telescope, ...... 

Lamp for mining engineering, of brass, with ground lens, 
Reflector, for illuminating cross hairs, .... 

Plummet lamp, ...... 

Large plumb-bob, weight 4 lbs., for use in shafts, 

Protection bag, ...... 

Bottle of fine watch oil, ...... 



lows: 

310.00 

20.00 

10.00 

5.00 

20.00 

10.00 

5.00 

8.00 

15.00 

13.00 

35.00 

7.00 

4.00 

10.00 

5.00 

1.00 

.25 



Part IV, Plate XII. 




A. Ljetz Company, 

Makers, 

San Francisco, Cal. 



No. 21. 

COMPOUND MINING AND SOLAR TRANSIT. 

Price Complete, $313. OO. 

For details, see the back of this plate. 



No. 21. 
COMPOUND MINING AND SOLAR TRANSIT. 

This instrument is like No. 9, with the Saegmuller solar attachment. 

It possesses a double center, lower clamp and tangential movement; plate move- 
ment with clamp and tangent screw, and sensitive plate levels; double verniers 
reading to minutes, placed conveniently for reading without stepping from the eye 
end. Compass needle and graduated compass ring, with variation plate. Cloth 
finished standards, carrying an improved telescope. The telescope is reversible and 
evenly balanced; it affords ample definition, power and light; fixed stadia hairs are 
supplied; it has a long level and possesses a clamp and tangential movement; also 
gradienter attachment; a full or half vertical circle reading to minutes. All gradu- 
ations are on solid silver. The instrument has the Lietz tripod coupling, and a 
shifting center. » 

The solar attachment is detachable, screws into the top of the telescope axis, 
and becomes a part of the instrument. It answers all the purposes of a side tele- 
scope, as shown in the marginal sketch. 

The whole instrument is packed in a handsome case, with a special place for the 
solar attachment, containing a plumb-bob, adjusting pins and all the usual acces- 
sories. 

Dimensions and Weight. 

Horizontal Circle (measured to edge of graduation), 
Vertical Circle (measured to edge of graduation), 
Compass Needle, . . . . 

Telescope, ....... 

Object Glass, ...... 

Magnifying power, 

Weight of instrument, .... 

" tripod, ..... 

" box, . . 

Weight of this instrument, if made of hard aluminium, 
The price of this instrument, complete, is 

And if made of hard aluminium, $363. 00. 



5 


inches diam. 


4 




" 


" 


3? 




" 


long. 


S 




" 


" 


1 




18 


diam. 




9 


lbs. 






6 


" 






6 


" 






5 


" 





$313.00 



The Extras, for which additional charge is made, are as follows: 

Adjustable Stadia Hairs, ..... 

Arrangement for offsetting right angles, 

Striding level to axis of telescope, .... 

Constructed with three leveling screws on base-plate, instead of four, 
Three leveling-screw shifting center, .... 

Prism attachable to eye-piece, . . . . 

Extra extension tripod, ...... 

Half-length tripod, ...... 

Detachable side telescope, ...... 

Lamp for mining engineering, of brass, with ground lens, 
Reflector, for illuminating cross hairs, .... 

Plummet lamp, ...... 

Large plumb-bob, weight 4 lbs., for use in shafts, 

Protection bag, ...... 

Bottle of fine watch oil, ...... 



$10.00 


5.00 


20.00 


10.00 


5.00 


8.00 


15.00 


" 13.00 


35.00 


7.00 


4.00 


10.00 


5.00 


1.00 


.25 







DL S 



No. 22. 

ENGINEERS' Y - LEVEL. 

Possesses all recent improvements. Long steel centre; star-shaped construction 
of the guide for the foot - screws; clamp and tangential movement; sensitive spirit 
level. The telescope has definition, light and power in a high degree; best achro- 
matic Jena glass lenses (erect vision) and stadia hairs if desired; is provided with a 
slide-protector, and either cloth, bright or bronzed finished. Fastened to the tripod 
by means of the Lietz coupling. 

The whole is packed in a neat case, containing all the usual accessories. 

Dimensions and Weight. 

Length of Telescope, . . . . .18 inches 

Diameter of objective, . . . If " 

Magnifying power, ..... 33 

Weight of instrument, ..... 10^ lbs. 

tripod, . . . . . 8 " 

" box, . . . . . 1\ " 

• Weight of this instrument, if made of hard aluminium, 6£ " 

The price of this instrument is ..... $145.00 

And if made of hard aluminium, $170.00. 



The Extras, for which additional charge is made, are as follows: 

Mirror, to control the bubble at eye end, .... $10.00 

Stadia hairs, fixed, . . . . . . .3.00 

" adjustable, . . . . 10.00 

Agate-fitted Y's, . . . . . .10.00 

Three leveling screws on base-plate, instead of four, . 10.00 

Protection bag, . . . . . . . . 1 . 00 

Bottle of fine watch oil, ...... .25 

gJ^Tf this instrument is provided with a micrometer screw for the vertical control 
of one of the Y's; and an additional spirit level, set normal to the line of collima- 
tion, it becomes a HYDROGRAPHIC Y-LEVEL. The charges for these additions 
are $40.00. 



Tart IV, Plate XIV. 




No. 23. 

15 -Inch Dumpy Level. 

Price, $90.00. 




With. mirror 

folded down.* 



No. 24. 

15 -Inch Dumpy Level, 

With mirror attachment. 
Price, $100.00. 



No. 24 

With mirror raised.* 



fHK A. I^ietz Company, 

Makers, 

San Francisco. Cal. 




*The mirror when folded down serves as a protection to the spirit level; when raised, it in- 
dicates the position of the bubble at the eye end of the telescope, so that the observer may con- 
trol it without changing his position. 

ffiflP-For details of the Dumpy Level, see the back of this plate. 



No. 23. 

ENGINEERS' DUMPY LEVEL. 

Long centre and most approved construction of the lower parts, with slotted 
star. Sensitive spirit level, placed over the telescope, to lower the centre of gravity. 
The telescope has definition, light and power in a high degree; best achromatic 
Jena glass lenses, erect vision and stadia hairs if desired. Is provided with a slide 
protector and cloth-finished. Fastened to the tripod by means of the Lietz coup- 
ling. 

Packed in a neat case, containing all the usual accessories. 

This is an elegant instrument, fit for the best class of surveyors' work, and is 
guaranteed in every detail. 

Dimensions and Weight. 
Length of Telescope, .... 15 Inches. 

Diameter of Objective, . . . . If " 

Magnifying power, .... 28 

Weight of instrument, . . . .9 lbs. 

" tripod, . . . 8 " 

" box, . . . . . 5-J " 

Weight of this instrument, if made of hard aluminium, 4£ " 
The price of this instrument is ..... $90.00 

And if made of hard aluminium, $115.00 



No. 24. 

Is the same as No. 23, but provided with a mirror to indicate the position of the 
bubble to an observer at the eye end. 

Price, . . . . . $100.00 

If made of hard aluminium, $125.00 



The Extras to Nos. 23 and 24, for which additional charge is made, 

are as follows : 

Stadia Hairs, fixed, . . . . . . . 3.00 

Horizontal Circle, reading to minutes, . . . - 25.00 

Protection bag, ...... 1.00 

Bottle of fine watch oil, . . . . . . . .25 



The German Level and Pocket Surveying Instrument. 



For many purposes where great accuracy is not required, 
it is often far more convenient to use some small instrument 
that will admit of measurements within practical limits. The 
irrigator, farmer, ditcher, grader, building contractor, gardener, 
forester, road builder, etc., often require means of obtaining 
heights and relative positions, for which a higher grade instru- 
ment would be unnecessarily refined. 

It is for the use of such men that we have imported a lev- 
eling apparatus, patented in Germany, that combines portability 
with accuracy and reliability, within reasonable limits, at a 
minimum expenditure. Such an instrument we now offer for 
sale. Specimens of it are shown on plate XV. It offers an ad- 
vantage in this, that bubble, cross-hairs and image may be 
viewed at the same time, for the bubble is not controlled from 
the outside, as usual in nearly all instruments, but, as in the 
case of a hand level, is regulated by looking through the tube, 
and adjusting it to the center by raising or depressing the tele- 
scope. (This holds good for all, except No. 28, which is a 
small dumpy level.) The magnifying eye-lens increases the 
size of the bubble several times, so that it may be accurately 
brought to the middle of the field. The instrument is made 
very compact, while its manipulation is so simple that anyone 
will be able to use it after a short practice. 

The level, when packed in a leathern case, may be easily 
put in the coat pocket. 

The instrument consists of a terrestrial telescope, having 
a magnifying power of from 10 to 15; an achromatic objective; 
and an appropriate eye-piece, allowing an extension of the eye- 
tube, with room sufficient to attach the level case underneath it. 

The instrument may be screwed into any support, like a 
heavy walking stick or a Jacob's staff, but we make for it a light 
tripod for convenient use. The ball and socket movement, just 
below the standard, admits of clamping in an upright position, 
so that the telescope axis may be placed approximately in a 
horizontal plane before finer adjustment is made. 



The focus is regulated by a motion of the eve-piece, and 
extension tube respectively. The former is pulled out far 
enough to make the cross-wires plainly visible; the tube is ex- 
tended until the image becomes clear and distinct, and remains 
stationary with the cross-hairs, when the eye is moved from side 
to side in front of the eye-piece, insuring a freedom from all 
parallax. 

In the tube is placed a mirrcy: at an angle of 45 degrees, hav- 
ing a circular opening in the middle, behind which the cross- 
hairs are located. Under the mirror lies the level vial, which 
is adjustable by two small screws. By means of an opening in 
the bottom of the case, light is admitted through the vial to the 
glass, and when the telescope is brought into a horizontal posi- 
tion, the bubble is seen standing vertically in the mirror by 
looking through the eye-end; and through the opening in the 
mirror appear the cross-hairs and the image. To obtain the 
horizontal position of the telescope, the large screw head at the 
objective end and below it is turned either up or down, until 

the reflected bubble is brought 
to appear evenly above and belov: 
the field of the cross-hairs, which 
is readily done by the eye (see 
marginal figure). At every turn 
of the instrument in a horizontal 
plane the bubble must be re- 
adjusted as described. 




RROR 
REFLECTED BUBBLE 



LEVEL BUBBLE 



Section of Level Telescope 



Attention is called to the fact that it is of advantage to 
bring the eye as closely as possible to the tube, so that the sur- 
face of the mirror may be in full view through the eye-lens. In 
case the instrument is used in a closed room, where the floor is 
dark, the bubble must be illuminated by holding under it a 
piece of white paper or some light object. 

Combinations are made and kept in stock, wherein this 
level is supplied with an azimuth compass, so that directions 
may be obtained as well. The higher-class combinations have 
a graduated plate, and admit of reading the horizontal angle 
to one minute of arc. They are also supplied with a vertical 
arc and with stadia hairs set 1 : 100 so that the instrument be- 
comes a little theodolite for manifold purposes. 




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GERMAN LEVEL AND POCKET SURVEYING INSTRUMENT. 

No. 25. 

Instrument mounted on strong tripod; ball and socket movement with clamp; 
horizontal movement with clamp and tangent screw; needle and compass, the ring 
graduated to degrees; telescope adjustable to focus; achromatic objective; adjustable 
eye-piece; the level bubble is viewed in the field like a Locke's hand level. The 
whole is packed in a neat wooden case. 

Dimensions and Weight. 
Length of Telescope, .... 8 Inches. 

Diameter of Objective, . . . . f " 

Length of Compass Needle, . . 2f " 

Magnifying power, . . . . • . 10 

Weight of instrument, .... 2 lbs. 

Price of this instrument, with tripod, .... $25.00 

Stadia Hairs, . . $3.00 extra. 

Small Plumb-bob, . . . 1.00 " 



No. 26. 

Is like No. 25, but instead of the compass it has a 3-inch horizontal circle, with 
a vernier reading to minutes. The whole is packed in a tine Morocco pocket case. 
Price, with Tripod, . . . . $30.00 

Stadia Hairs, . $3.00 extra. 

Small Plumb-bob, 1.00 " 



No. 27. 

Is like No. 25, and in addition possesses a 3-inch vertical arc. Packed in neat 
wooden case. 

Price, with Tripod, . . . $35.00 

Stadia Hairs, . . $3.00 extra. 

Small Plumb-bob, . 1.00 " 



No. 28. 

This is a small dumpy level of firm and substantial construction. It has level- 
ing screws with opposing springs, operating through a star, suspended over the 
center. Provided with a horizontal circle, with vernier reading to minutes. The 
telescope is adjustable to focus; achromatic objective, with protection cap; adjustable 
eye-piece; the 4-inch spirit level is mounted on top of the telescope. Packed in a 
neat wooden case, with the usual accessories. 



Dimensions 


and 


Weight. 




Length of Telescope, 






10 inches 


Diameter of objective, 






i 


Diameter of horizontal circle, 






4 


Magnifying power, 






15 


Weight of this instrument, 






3 lbs. 


Price, with Tripod, 




$40.00 




Stadia Hairs, 




$3.00 extra. 





Its cost is within the reach of all, and we know of no pres- 
ent better adapted to the young student, than one of these 
complete little field instruments, with which so much can be 
accomplished, and so much can be learned. Every manipula- 
tion of the theodolite is represented here, and it admits of obtain- 
ing results approaching those of the ordinary land surveyor's 
compass and level. 

Crude instruments are placed on the market to supply the 
demand for a fairly reliable measuring tool at small cost; these 
are usually worthless, as they are made without any regard for 
the underlying principles that should govern the make of such 
an article. But with our German pocket instrument, which is 
protected by letters patent in the Empire, the object has been 
attained. It is perfectly reliable within the scope for which it 
was intended. Every part is carefully made and nicely finished, 
and its cost is less, in comparison, than the article that is usually 
displayed with nails, pots and frying-pans in the windows of 
our hardware stores, or together with a profuse sprinkling of 
cheap spectacles and toy microscopes, in the show-cases of cer- 
tain dealers, who would not know the use of such an instru- 
ment, if it ever had any. 




SEISMOGRAPH 



The engraving shows an improved and simplified seismo- 
graph, as suggested- by E. Brassart, of the Geodynamic Institute 
in Rome, Italy. Excellent results have been achieved, and we 
would recommend the use of such an apparatus, or a similar 
one, in our Pacific Coast States, where so little is done in re- 
cording earthquake phenomena, and where the opportunities 
are frequent for a systematic research in this field of science. 
We know that a few instruments are in use, but these are in 
nearly all cases only registers for the horizontal component of 
the earth's motion, simply presenting to the eye a spider's 
web of lines giving in a general way the magnified amount 
of the motion, and possibly the direction. The vertical com- 
ponent, however, is just as essential, and an instrument that 

will not record this is incom- 
plete and of small utility. 

With the apparatus shown, 
both components of the shock 
motion are registered with all 
the accuracy required. The well 
known principle involved is that 
the heavy weight remain abso- 
lutely stationary during a move- 
ment of the earth. It is justly 
claimed that the peculiar meth- 
od of suspending it in this case 
will assure accuracy in reference 
to the horizontal motion, and 
the spiral spring arrangement, 
similarly, in recording the ver- 
tical component. The inertia 
of the mass is effected by the 
well considered construction of 
the whole apparatus. 

We shall not go into a detailed 
description here, but will fur- 
nish every information cheer- 
fully upon application. The 
Company is in a position to 
build seismographs on this prin- 
ciple, and the charges for the 
work will be most reasonable, 
in order to encourage a system- 
atic investigation in California, 
a country so prolific in these 
interesting phenomena. 






^ 



PLANE TABLES. 

No. 29. 

This is the stjde used in the topographical work of the U. S. Coast and Geodetic 
Survey, containing all the parts necessary for a proper equipment of the table, and 
an alidade of the most approved pattern. The table is so made that a change from 
temperature or humidity is impossible. Its dimensions are about 24 inches square. 
The telescope is achromatic, and of sufficient power for accurate stadia measure- 
ments; the stadia hairs are always supplied. It may be either erect or inverting. It 
is furnished with a vertical arc and an accurate striding level. The table has a 
plumbing bar, and the alidade a box compass and a circular level. Furnished with 

an elegant case. 

Dimensions. 

Size of Table, . . . . .24 inches square. 

Length of Ruler, . . . 21 '' " 

Length of Needle in box, . . 4 " " 

Length of Telescope, . . . 15 " " 

Radius of VerticaLArc, . . 3| " " 

Magnifying Power, . . 32 

The price of this instrument complete as described and shown on plate is .}'300.00 

No. 30. 

An improved table and alidade, the latter either of brass or aluminium, as used 
in the topographical work of the Geological Survey; the alidade having been espec- 
ially designed for mountain surveys by the able officers of that department. Every- 
thing is made with a view to insure compactness. Supplied with all the necessary 
accessories. 

Price, complete, with brass alidade, ..... .^300.00 

With aluminium alidade, $330.00 



Part IV, Plate XVII. 



4 2 
3 3 


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3: 6 1 
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The A. Ijetz Company, 

Makers, 

San Francisco, Cal. 



No. 31. 

Leveling Rod. 

Price, $17. OO. 



Nos. 32 to 34. 

Ranging Poles. 

Price, $2.75 to $3.00. 



(See details on the back of this plate, and marginal note.) 



LEVELING RODS. 
No. 31. 

Philadelphia self-reading rods, with vernier clamps and target, reading to 
lOOOths; from 6 to 8 feet long. Slides out to 13 feet. 

Price, . . . . $17.00 

No. 31 A. 

Mining rod, 3 feet long, sliding out to 5 feet, with vernier clamps and target, 
reading to lOOOths. 

Price, . . . . . $14.00 

RANGING POLES. 
No. 32. 

Wooden pole, 6 and 8 feet long, with steel pointed shoe, divided in feet, red and 
white alternately. 

Each, . . . . . $2.75 

No. 33. 

Octagonal steel spear, 6 to 8 feet long, divided in feet, red and white alternately. 
Each, . . . . $3.00 

No. 34. 

Of half-inch iron pipe, with pointed steel shoe, divided in feet, red and white 
alternately. 

Each, . . . . . $3.00 

FLEXIBLE RODS. 
.No. 35. 

For Leveling and Stadia Work. 
Painted on either heavy or light canvas, with a legible design to read to hun- 
dredths of a foot. The numerals of the tenths are black and one-tenth of a foot high; 
the foot numerals are red and two-tenths of a foot high. Length, 10 or 12 feet. 
May be rolled up in a package 1\ to 3 inches long (the width of the canvas), and less 
than H inches in diameter, weighing less than 3 ounces. A very handy requisite 
on a long trip. 

Price, 10 feet long, . . $3.00 

12 " . . 3.25 




No. 36f. 

EQUATORIAL. 

9-inch aperture; focal length, n' 10' 

(See the following page.) 
(t See introduction to Part IV.) 



EQUATORIAL REFRACTORS. 

Improved mounting upon a rectangular pillar, containing the strong driving 
clock. 

All necessary adjustments and manipulations possible from the eye-piece. 

The telescope possesses a number of astronomical and micrometer eye-pieces, 
varying in power with the size of the instrument, from 40 to 1200. 

The diameter of the aperture varies from 31 inches to 12 inches, and the focal 
length from 4 feet 5 inches to 15 feet 9 inches. 

Has one or two ring micrometers, the declination circle reading to 5 seconds of 
arc, the hour circle to 2 seconds of time. 

The finder has an aperture of from 2 to 3 inches. 

The smaller sizes may be had with or without driving clock. 

All the necessary accessories are supplied. 

Prices vary with the size and style, ranging from 6500.00 to 825,000.00. 

We invite correspondence on this subject, and will furnish prices upon appli- 
cation. 



PORTABLE 

MERIDIAN INSTRUMENTS. 

With rectangular prismatic telescope.) 

The lower frame of these instruments is of cast iron, containing a mechanical 
device for rapidly reversing the axis, without removing the spirit level. Graduated 
circle at the eye-end of the axis. Micrometer eye-piece; adjustable central illumi- 
nation of the field through the axis, the latter balanced on friction rollers. Adjust- 
able in azimuth. Furnished with a number of eye-pieces, varying with the size of 
the instrument; the power ranging from 48 to 160. 

The diameter of the circle may reach 10 inches, and the distance between bear- 
ings, 25 inches. 

These instruments are made in different sizes, the diameter of the aperture 
varying from 2£ to 3 inches, and the focal length from 25 to 38 inches. 

All necessary accessories supplied. 

Correspondence invited and detailed prices furnished upon application. 




No. 37f. 
MERIDIAN INSTRUMENT. 

With rectangular prismatic telescope, eye-piece at axis. 234 -inch aperture, 
focal length, 33 inches. 

Price, $950.00. 

(See the opposite pagej 



No. 38. 

ALT-AZIMUTH INSTRUMENT. 

Circles 11 inches in diameter. Micrometer microscopes, reading to seconds 
direct; with additional reading-glasses to verniers. Telescope has an aperture of 
If inches, and a focal length of 20-i inches. Power. 40 and 60. 

Auxiliary telescope with eve-piece micrometer as shown. Maybe clamped to the 
iron ring of the base, upon which it slides. The eye-pieces of the telescopes are 
interchangeable. 

All accessories furnished. 

Complete in two fine packing cases. 

Different sizes are made of the same style at different price-. 

Correspondence is invited, and detailed information will be furnished upon 
application. 

Note. — These alt-azimuths are elegant instruments, which are a specialty of 
the manufacturing firm. The general construction an 1 the shape is that of Pistor 
& Martin's, but a number of recent improvements have been added by the present 
makers, so that the instrument is an absolute standard in every particular. The 
graduations are made with great precision on a dividing engine one meter in diam" 
eter. 

We recommend these instruments; they have a European reputation, and are 
not excelled bv anv other make. 




No. 38f . 



ALT-AZIMUTH INSTRUMENT, 

With auxiliary telescope, 
n-inch circles. 

Price, $1,400.00. 

(See opposite page.) 



Part IV. 




No 39f- 
ALT-AZIMUTH INSTRUMENT. 

Circles 7 inches in diameter. Microscopes read directly to 5 seconds. 
Telescope, 13-inch focal length and i^-inch aperture. Power, 25 and 36. 

Price, $700.00. 



Part IV. 




No. 40f. 
ALT-AZIMUTH INSTRUMENT. 

Circles, 5% inches diameter: verniers read to 10 seconds with reading-glasses. ^Tel- 
escope has a focal length of g l A inches and a i^-inch aperture. Power, 20 and 30. Ad- 
justable eye-piece. Striding level and level to vertical limb. Reversible axis. 

Price, $450.00. 



THEODOLITES WITH MICROMETER -MICROSCOPES. 

The horizontal circle is read by two opposite microscopes directly from 1 to 5 
seconds; its diameter varies from 7 to 14 inches. The vertical circle has a diameter 
of from 5 1 to 9f inches; it is read by two opposing verniers that indicate 5 or 10 
seconds. This circle may be omitted. The telescope may be either in the middle 
or at the side; axis reversible. 

The dimensions and optical powers of the telescope vary within the same limits 
as in the case of the preceding alt-azimuth instruments. Striding level for telescope 
and fixed level for horizon. 

Packed in two cases. 

Price varies with the size and the accessories desired. 

We invite correspondence and will furnish figures upon application. 

The instruments are of the highest grade. 




No. 41 f. 
THEODOLITE WITH MICROMETER- MICROSCOPES. 

Horizontal circle, 8K inches diameter. Both microscopes read 5 seconds direct. 
Striding level to telescope, 

Price, $650.00. 

With vertical circle, 6y 2 inches diameter, reading to 10 seconds, by double verniers, 

Price, $750.00. 

(See the opposite page.) 



Part IV. 




No. 42f . 



REFLECTING CIRCLE, 

Mounted on a Brass Stand. 

Has two prisms. Circle, io# inches diameter, with two verniers reading 10 seconds. 
Measures angles from o to 36.0°, which is made possible by the peculiar shape of the 
prisms. Provided with three pairs of colored shades. Telescope has an aperture of yi 
inch, with two astronomical eye-pieces; power, 6 and 10; and one terrestrial eye-piece 
of 3. Prismatic eye piece, etc. 



Price, as shown, $245. OO. 



Part IV. 




No. 43f. 



REFLECTING CIRCLE, 

For Nautical Purposes. 

Diameter, 10 inches. Complete with telescope, having two astronomical eye-pieces. 
Verniers reading to 10 seconds. Measures angles from o to 288 . Prismatic eye-piece. 
Three pairs of colored shades. 

Complete with brass stand and lamp for night observation. 

Price, $220.00. 

These REFLECTING CIRCLES and SEXTANTS are made in great variety as to size 
and style. 

Correspondence is solicited and prices will be furnished upon application. 



AMSLER'S PLANIMETER, 

(IN GERMAN SILVER) 

Arranged for Measuring Areas in either Metric or English Units. 
Price, $30.00. 




No. 44. 

This very useful instrument for obtaining areas is so well 
known to the engineer that it need not be described in particu- 
lar. A theoretical discussion of the principles underlying its 
operation will be found in almost any handbook on higher sur- 
veying. 

Instructions how to use it are published by Amsler, which 
are given below: 

"Adjust the sliding-tube 011 the bar so that the index mark on the tube coin- 
cides with one of the marks on the bar. The unit of area is engraved to the right 
of the corresponding mark. Then proceed as follows: 

"Needlepoint outside the diagram. — Put the instrument 011 the drawing surface 
with the tracing point at a mark on the curve, the area of which is to be measured, 
press the needle-point slightly into the paper outside the curve and read off the 
rolling wheel and the counting disk, taking the whole circumference of the recording 
roller as the unit of reading. (The roller need not be set to zero.) Then move the 
pointer (or tracer) around the area in the direction of the movement of the hands of 
a watch, and when you reach the starting point take a reading. Subtract the first 
from the second reading, and multiply the remainder by the coefficient of the scale. 
"Example: Area required in square feet. Slide the tnbe on the bar so that 
the index of the former coincides with the mark denoted by 0.1 square ft. Sup- 
pose the dimensions of the diagram allow the needle-point to be placed outside. 
Then 

Second reading (say) S.311 

First reading (say) 2.322 



5.989 X 0.1 = 0.59S9 square feet. 

"Needle point inside the diagram. — Circumscribe the diagram with the pointer 
in the direction of the movement of the hands of a watch, observing at the same 
time the counting disc, in order to see whether the total rotation is a forward or a 
backward motion. 



" This preliminary rough operation completed, proceed as before explained, now 
following the curve carefully with the pointer. If the total rotation of the roller 
has been aforivard motion, subtract the first reading from the second, and add the 
difference to the figure engraved on the top of the bar just over the mark. 

Thus, in a similar example: 

Second reading 5.423 

First reading 3.004 



2.419 

Figure on top of bar 20.741 



23.160 X 0.1 .= 2.316 square feet. 
The figures on the top of the bar are slightly different for different instruments. 

" If the total rotation of the roller is a back motion, subtract the second reading 
from the first reading, and subtract the difference from the figure on the bar. 

" Note: When the mark on the roller is at the mark of the vernier, a mark 
of the counting disc should be opposite the fixed index mark. Any slight non- 
coincidence due to play between roller and disc may readily be allowed for in taking 
readings." 

The engineer finds this instrument most useful in deter- 
mining the areas of profiles drawn upon cross-section paper, 
and it is there nearly always the case that the needle-point is 
placed outside of the diagram. 

These profiles are generally drawn on an exaggerated scale, 
the vertical scale being considerably larger than the horizontal 
one. 

The best means of obtaining the area of such a profile is 
to draw a rectangular figure on the same scale, or scales, of a 
known area; to circumscribe that area with the planimeter set 
arbitrarily, but well fastened so that the bar cannot slip, and to 
read the disc, roller and vernier. The starting point may have 
been or not; in the latter case we note the difference. 

The figure may be circumscribed several times and the 
mean taken, should we desire greater accuracy. Knowing the 
area of this rectangular figure, it is an easy matter to compare 
it with the reading of the planimeter, and to find a coefficient 
by which every planimeter determination of the area of any 
profile drawn on the same scale, or scales, of the test figure 
must be multiplied to give the true result in square units rep- 
resented by the scale. This is so apparent that it need not be 
demonstrated. It is by far the safest method, as it will recog- 
nize not only scale exaggeration, but any inaccuracies in the 
divisions of the cross-section paper. If we want to be very 
precise, we may determine a coefficient for every sheet of the 
cross-section paper used. 

The instrument we keep in stock is Amsler's Planimeter, 
No. 4 (German Silver), price $30; but we will, upon order, 
procure for our customers any one of the highest grade plani- 
meters, or Integrators for measuring areas, moments and mo- 
ments of inertia. We invite correspondence on this subject. 



SURVEYOR'S COMPASS. 

No. 45. The instrument has a 5£-inch needle, 14-inch plate, open sights, in 

box with strap §45 00 

No. 46. The same with variation plate 50 00 




Pocket Compasses, with folding sights, varying in price from $6 00 to $25 00 




No. 4: 



No. 47. 

Prismatic Compass, 3 inches diameter, with divided ring on needle 
and folding sights; packed in neat case, very convenient for recon- 

noissance |15 00 

These Compasses range between $15 00 and $48 00. 




Small Pocket Compasses, with or without sights, ranging in price from $1 00 to $8 00 

No. .48. Miner's Compass, or Dipping Needle. An instrument for determin- 
ing the location of iron by means of a magnetic needle. Price. . . .$14 00 

No. 49. Prospector's Pocket Balance, for making a field analysis of minerals. 

Price $12 00 




No. 50. 

No. 50. Lock's Hand Level, with prism $8 00 

No. 51. Lock's Hand Level, with plated mirror 5 00 

No. 52. Abney's Kenecting Level or Pocket Altimeter, improved, with divided 

arc to show gradients, in morocco case, each 15 00 

No. 53. Abney's Eeflecting Level or Pocket Altimeter, with bar needle, com- 
pass and socket for Jacob staff 18 00 



A NEW CLINOMETER. 

The accompanying cut is abont half size and represents i new clinometer, de- 
signed by Melville Attwood for the nse of the miner and prospector. It can easily 
be carried in the pocket and is made as small as possible consistent -vrith accuracy. 

No, 54. 




Attwood's Clinometer, showing Compass, 
I s the graduated circle, which is kept in place by a small spring at A, a slight 
i be -re on the knob of which sets the circle free, and on the removal of the fingers 
the instrument can be taken up and the angle of inclination easily read. 
D represents a compass for taking approximate beari:i e - 
B an - :-.: e ^_iall levels, one on the top and the other at the end of instrument. 




Circle of Attwood's Clinometer. 
With this clinometer and a small straight-edge the under lay of any metalliferous 
vein may be accurately taken, and in positions where a larger instrument could not 
be used: also the dip of anv bed. or stratum of rock or seam of coal. 

Timbering of anv level shaft or incline may be set by it. It can be used in 
quartz mills to give the proper angle to the silvered plates, blanket, trays, and sluice 
boxes. The instrument is a very practical one. 

N 54. Attwood's Clinometer in wooden frame, as illustrated above f 10 00 

Xo. 55. ''• metal case 25 00 



ILLUMINATING LAMPS. 

No. 56. Lamp for illuminating graduations, cross-wires, etc., for use in un- 
derground work, common $ 4 00 

No. 57. Lamp of brass, with ground lens 7 00 

No. 58. Small Plummet Lamp of brass, steel point 8 00 

No. 59. Large " " " " 10 00 

Plumb Bobs of the most improved shape and of any desired size and 

weight, from $1 00 to $5 00 



SURVEYOR'S CHAINS. 



No. 60. 
61. 
62. 
63. 
64. 
65. 
66. 
67. 



Iron Chain, brass handles, No. 8 wir 



Steel 



68. Steel 

69. 
70. 
71. 



Chains, 



No. 10 



Chains, brazed links and rin 



•e, 33 i 
< 50 
' 66 
' 100 
' 33 
' 50 
66 
' 100 


eet 


.... $ 2 60 
.... 3 25 


" * 


.... 4 00 
.... 5 25 


it 


.... 3 50 


I ( 


.... 4 25 


i k 


.... 6 50 


{( 


.... 8 00 


» No. 


12 wire, 33 feet 


.... 5 50 




50 " 


.... 6 00 


i i 


66 " 


.... 10 00 


<( 


" 100 " 


.... 11 50 



CHAIN PINS AND MARKERS. 



No. 72. Steel Arrows, H in a set $1 50 

No. 73. Marking Tool, timber scribe for surveyor's use 1 25 



No. 


,74 


< i 


75 


" 


76 


" 


77 


" 


78. 


" 


79 



TAPE LINES. 
Chester man's Steel Tapes. 

25 feet $ 4 50 

33 " 5 50 

50 " 7 50 

66 " 10 00 

75 " , 1150 

100 " 12 00 



Chesterman's Metallic Tapes. 

No. 80. 33 feet $2 25 

" 81. 50 " 2 75 

" 82. 66 " 3 00 

" 83. 75 " 3 75 

" 84.100 " 4 50 



Paine's Patent Standard Steel Measuring Tapes. 

The popularity and rapidly increasing demand for these steel tapes evinces the 
fact that they have become indispensable in all measurements where accuracy is re- 
quired, and also as a standard for testing tapes or chains for ordinary work, as all 
woven tapes and chains are liable to variations. They are made so as to be readily 
detached from the case and a pair of compensating handles (to provide for variations 
of temperature) attached, and can be used with more facility and far greater accu- 
racy than a surveyor's chain. 

Paine's Patent Standard Steel Tapes. 

IN JAPANNED CASES. 

No 85 86 87 

Feet 5 10 15 

Price, each $1 50 2 00 2 50 

No 90 91 92 

Feet 33 50 66 

Price, each $4 50 6 00 8 00 10 00 12 00 

Paine's Patent Standard Steel Tapes. 

IN LEATHER COVERED CASES, FLUSH HANDLE. 

No 95 96 97 98 99 

Feet 33 50 66 75 100 

Price, each $5 50 8 00 10 00 12 00 15 00 

Measures without cases, ten cents per foot. 

GRADUATED COMPENSATING HANDLES. 

FOR VARIOUS TEMPERATURES. 

Per pair $3 00 

Pocket Thermometers, each 1 50 

Grummon's Balance and Level, each 4 00 



88 


89 


20 


25 


3 00 


3 50 


93 


94 


75 


100 



HODGMAN'S STEEL RIBBON TAPE OR TAPE CHAINS. 




The general favor with which these tapes are received shows that in the future 
they will take the place of the heavy chains, with their hundreds of wearing {places. 

These tapes are intended for use wherever the chain can be used, and in many 
places where it cannot. They are not intended to take the place of the light, finely 
graded ones, but are especially designed for convenience and durability, and to take 
the place of the chain in all land surveying, railroad and canal work and town platting. 

Made of the best tempered and "polished and blued" steel wire, 5-32 to 5-16 
inch in width and Nos. 30 to 36 in thickness. For tapes of 100 feet or under, we 
would use i inch No. 32. Wider ribbon is more apt to get "kinked " and broken, 
and is more affected by the wind. The graduations are made on a surface of fine 
Babbitt Metal, of sufficient thickness to receive and retain the figures, which are of 
a size corresponding to the width of the tape. 

The tape is not easily broken by fair usage, but should an accident of that kind 
occur, it is easily mended by brightening the surface near the ends, then clasping 
them with a sleeve of thin brass or tin, and letting a little solder flow in, being care- 
ful, of course, to keep the ends butted together and keep it straight while cooling. 

The handles are made to unship, that by drawing the tape through the brush it 
is not liable to catch anywhere. 



No. 


Length. 


No. 1. 


No. 2. 


No. 3. 


No. 4. 


No. 5. 


No. 6. 


100 
101 


50 feet 

100 " 


|1 50 
2 50 

4 50 

5 00 

6 00 
1 50 

1 50 

2 25 
4 00 
4 50 
9 00 


$2 00 
3 00 

5 50 

6 50 
8 00 
2 00 
2 00 
2 75 
5 00 
5 75 

11 50 


$2 75 
3 75 

5 50 

6 00 

7 00 
2 00 


$ 3 50 
6 00 

11 00 
14 00 
16 00 

5 00 

3 25 

5 50 

10 00 

12 50 
22 00 


$ 3 75 

6 50 

11 50 

14 50 

16 50 


$ 5 50 
8 00 


10 s ? 


200 " 


13 00 


103 


250 " 


16 00 


104 
105 


300 " 

Each additional 100 


18 00 


106 


50 links, 33 feet 


5 25 


107 


100 " 66 " 


7 50 


108 


200 " 


12 00 


109 


250 " 


15 00 


110 


500 " 


25 00 



No. 1 graduated each 10 feet or links. 

a 2 " " 5 " " 

"3 " " 10 " " first 10 each foot. 

"4 " " foot or link. 

"5 " " foot or link, first one in lOths or 12ths. 

" 6 is No. 4 complete with reel and handles. 
Reel, $1 50; pair of handles, 50 cents. 



ROD LEVEL. 

No. 111. Level, for plumbing a rod or a sight-pole, made to fit the edge of a 

rod or pole $3 50 






SEXTANTS. 

No. 112. Sextant of gun metal, light, but very strong, 7-inch radius, 120 
degrees, graduated on silver to 10 minutes, vernier reading to 10 seconds, 
2 astronomical telescopes magnifying 6 and 10 times, 1 terrestrial tele- 
scope, object glass, 1£ in., seven neutral glasses and two reflecting 
mirrors. Instrument complete in polished mahogany box, each $120 00 

We keep supplies for sextants always on hand. 

No. 113. Pocket Or Box Sextant. A small instrument, encased in a 
brass box; has a telescope sight and colored glasses attached, so that it 
may be used for both field and nautical observations $42 50 

(a) Angle Mirrors or Prisms. Small pocket instruments for laying off 

right angles. Useful in field work. Price varies from §5 00 to §10 00 

ARTIFICIAL HORIZONS. 

No. 114. Mercurial Horizon, iron trough, iron bottle with screw stopper and 

funnel cap, glazed metal roof. All in polished mahogany box $27 50 

No. 115. Keflecting Horizon, black glass plane mounted in brass, with three 

leveling screws and spirit level, in polished mahogany case, each 16 00 

HELIOTROPES. 

No. 116. Gauss' Heliotrope . % $150 00 

No. 117. The telescope body is an iron tube, in the middle is a wood screw 

with joint for attaching the instrument to a tree or post. Price in box, 30 00 
No. 118. Heliotrope as made by us for the United States Coast and Geodetic 

Survey, with wooden base, mirrors 4x4 35 00 

No. 119. Same as before, but with mirror 6x6 41 50 

No. 120. Same, with mirror 8x8 48 50 

Prices for larger sizes on application. 
No. 121. Pocket Heliotrope, Steinheil's, a beautiful instrument that requires 

no adjustment. In case 25 00 

Extras to Heliotrope, Nos. 118 to 120 inclusive. 

Tangent screws for vertical and horizontal movement 7 50 

Outlifting arrangement for tangent screws 5 00 



GET YOUR BAROMETER RATED. 



In our mountainous countries where, during the summer months, the atmos- 
pheric pressure remains nearly stationary, the value of the aneroid barometer for 
determining differences of level cannot be overestimated, and, indeed, the instru- 
ment is quite extensively used for that purpose. 

Complaints are frequently made, however, that no reliability can be placed in 
the accuracy of these determinations. Considering the very delicate mechanism 
intended to measure minute differences in air pressure, it seems reasonable that an 
instrument of that kind should be rated, and that it should be supplied with a 
correction table, giving certain values that must be either added to or subtracted 
from the observation for different pressures, in order to obtain a correct altitude. 
We are quite sure that in most cases the rating would be all that is necessary to 
make the barometer a comparatively reliable instrument of measure. In the case of 
the Goldschmid Aneroid, every instrument is carefully tested by crossing with it 
the mountainous regions of Switzerland, and comparing its readings with known 
elevations at different stations. The table of correction is then computed and 
placed in the case. 

In order to enable us to make similar tests for the purpose of barometer rating, 
we have recently designed and built a new and most sensitive pneumatic apparatus, 
with which we are in a position to obtain a reliable rate for any barometer that may 
be sent to us for trial. These 

Correction Tables will be furnished at a Cost of 
$2.50 for each Aneroid. 

For the very high grade instruments it is the custom to attach corrections for 
temperature in different altitudes; but unless very great accuracy is required, it is 
not necessary to consider these. For ordinary purposes, and in practical work, 
such as is called for by this method of measuring, these corrections may be safely 
omitted. Should they be required, however, for hypsometrical work with fine 
instruments, we will furnish tables showing the corrections due to temperature 
under different pressures. The charge for such a table is $5.00. 



(a) 



ANEROID AND ALTITUDE BAROMETERS. 




Prices from $12 to $60, according to size and altitude scale. 

Aneroid barometers are made expressly for us by the best makers, in German 
silver or nickel plated cases, truly compensated for temperature, with or without 
thermometers, ranging from 5,000 feet to 20,000 feet, size, If, 2\ and 5 inches. 
Guaranteed correct, every one being subjected to a severe test before being sold. 

MERCURIAL STANDARD MOUNTAIN AND SEA 

BAROMETERS. 

Prices from $20.00 to $100.00. 

Supplies for these barometers, as tubes, mercury packings, etc., we have con- 
stantly on hand. 



Goldschmid Aneroid, as made by Hottinger of Zurich, complete in 
leathern case, with thermometer and tables showing rating, graduated 
to read to millimeters (see description of this instrument in Part III 
of this Manual). Prices range from $50 00 up 



(b) 



ACHROMATIC FIELD AND MARINE GLASSES 
AND TELESCOPES. 







Prices vary according to size and quality, and range from SS.oO to S2o.OO 

BINOCULAR TELESCOPES. 
Tli--- teles :e similar in construction to the ordinary field glasses, but 

possess a much higher magnifying power; for this reason they are very extensively 
used, especially where a large field in connection with a high power is desirable. 

Prices from S25.00 to $52.00. 



ODOMETERS. 

122. l:iLt:er for measuring distances by wagon. Ir := enclosed in a 
3fl box, 4j- inches iiameter, furnished with leathern case and double 
straps to fasten to the center of the wheel. It is the most correct instru- 
ment for practical use. Price $17 00 



PEDOMETERS. 

Pedometers are pocket instruments for measuring the distance traversed in 
walking, the number of miles being registered by a mechanism inclosed in a nickel- 
plated watchcasing, and operated by the motion of the body. 
No. 123. Pedometer, watch pattern, nickel case, lf-inch, registering 12 miles 

by i mile. Price $4 50 

No. 124. The same; registering 50 miles by 80 yards 5 25 

No. 125. The same; registering single steps up to 100,000 $6 50 

Level constructed for the use of Millwrights, Machinists 
and Carpenters. The iron frame is 28 inches long; has two adjustable levels 
6 and 3 inches long. 

No. 126. With common levels $15 00 

No. 127. Same, with ground levels 20 00 

(a) Anemometers or Wind Gauges, improved pattern. Prices from $17 00 
to $35 00. 

No. 128. SACCHARIMETER. 

An instrument for estimating the percentage of sugar in fluids. 

With tube for liquids, 8 inches long, made to slide in-a brass tube, that carries 
a polarizer and double quartz plate at one end, and at the other an analyzer with 
divided circle. The circle is graduated to thirty minutes and may be estimated to 
six minutes with accuracy. 

Observation is made by adjusting the so-called transition color on both halves 
of the quartz plate, the tube being directed by hand towards a white surface. Suit- 
able for fluids containing a small percentage of sugar. Complete with directions. 

Price $40 00 

No. 129. POCKET SPECTROSCOPE (Browning's pattern), for observ- 
ing the effect of absorption in larger objects, with adjustable slit and Amici prism 
of high dispersion. 

Without comparison prism $20 00 

With " " 30 00 



(a) MICROSCOPES. 

We keep in stock microscopes for professional purposes. 
Special designs made to order. 

(b) EQUATORIAL MOUNTINGS. 

Portable equatorial mountings are made to order for the amateur, for schools 
and colleges, from $35 00 to $150 00. 

(c) POCKET MAGNIFIERS. 

Beading glasses especially adapted for observing the vernier and needle of tran- 
sits, single or double glasses, in hard rubber or celluloid cases, from 50 cents to $2 00. 



(A) DRAWING INSTRUMENTS AND SUPPLIES. 

Different grades and styles are constantly kept in stock, in sets as -well as in 
single pieces. We furnish our patrons with any desired make and will send prices 
upon application. 

Single instruments always on hand, consisting of dividers, plain and with the 
accessories of pin point, extension leg, pencil point, pen, etc.; proportional dividers; 
bow pens and pencils; steppers; beam compasses; drawing pens; dotting pens; road 
and- railway pens; curve pens; folding and rolling parallel rulers, etc., etc. 

Drawing paper of any desired quality is supplied, as well as cross-section paper, 
profile paper, tracing cloth, tracing paper, drawing pencils, rubber, colors and color 
dishes, brushes, thumb tacks, note books for field and office. We can always fur- 
nish our customers with office supplies of any kind at the shortest notice. 

Drawing boards or trestles, or anv combination made to order. 



(e) PROTRACTORS. 

Three-armed protractor or station pointer, as used in plotting hydrography 
by the U. S. Coast and Geodetic Survey, graduated to read to minutes, 
with verniers and reading glass, extension arms and center plugs, com- 
plete in fine case, securely packed $80 00 

Cheaper grades upon application. 
These articles will be made to order to suit any particular line of work. 

Circular and semi-circular German silver protractors, graduated as required, 

with or without verniers, from 60c. to $20 00 

Paper, horn, ivory and boxwood protractors, from 15c. to glo 00 




SCALES. 



k>. 130. 


Flat Boxwood Scale, 6-inch, div. 10x50 parts to the inch 


" 131. 


" 


" 6 " " 20X40 " 


» 132. 


" 


" 6 " " 30X60 


" 133. 


" 


" 6 " " 80X100 " 


" 134. 


" 


" 12 " " 10X50 " 


" 135. 


" 


" 12 " " 20X40 " 


" 136. 


" 


" 12 " " 30X60 


" 137. 


" 


" 12 " " 80X100 " 


" 138. 


Flat Cellul 


oid-edged Scale, 6-inch, div. 10x50 parts to the 


" 139. 


" 


" 6 " " 20X40 " 


" 140. 


i t 


" 6 " " 30X60 " 


" 141. 


" 


6 " " 80X100 " 


" 142. 


" 


" 12 " " 10X50 " 


" 143. 


" 


" 12 " " 20X40 " 


" 144. 


" 


" 12 " " 30X60 " 


" 145. 


" 


" 12 " " 80X100 " 



each 



inch, each 



$0 50 

50 

. 50 

. 1 00 

75 

75 

. 75 

. 1 50 

85 

85 

85 

35 

25 

25 

25 

00 



Foot divided decimally. 

No. 146. Flat Celluloid-edged Scale, 12-inch, div. 100X500 parts to the foot, ea., |1 50 
" 147. " " " 12 " " 200X400 " " " " 1 50 

" 148. " ". " 12 " " 300X600 " " " " 1 50 

" 149. " " " 12 " " 800X1000 " " " " 2 50 

Triangular Boxwood Scales, Engineer's, div. 10, 20, 30, 40, 50, 60 parts to the inch. 

No. 150. 6-inch, each $0 80 

" 151. 12 " " 150 

Triangular Celluloid-edged Scales, Engineer's. 

No. 152. 6 inches long, divided like Nos. 150 and 151, each $2 00 

" 153. 12 " " " " " 150 and 151, " 3 00 

Divided for Architects at same prices. 
|!$KS=ij»Any particular scale, for any purpose whatever, upon any material, engraved 
liNSSfc to order. 

TRANSPARENT AMBER TRIANGLES. 

30x60°— Inches, 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 
No. 154. Each, . $0.35.45.55.65 .75 .85 1.00 1.20 1.45 2.00 2.50 3.25 

45°.— Inches, 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 
No. 155. Each, $0.45 .55 .65 .75 .90 1.10 1.25 1.45 1.80 2.20 2.75 2.75 3.50 4.25 
Amber Lettering Angles, per set (3) $2.00 



No. 



Inches, 
156. Each, 



MAHOGANY STRAIGHT-EDGES. 

TRANSPARENT AMBER EDGES. 

18 24 30 36 42 48 54 60 

$1.25 1.50 1.75 2.50 3.25 4.00 4.75 5.75 



Triangles and Curves of rubber and wood kept in stock and supplied. 



SLIDE RULES. 

No. 157. Dennert & Pape's logarithmic slide scale, 10 inches long, celluloid 
covered, graduated as described in the discussion of the use of this scale 
in Part III of this Manual $4.50 






McCULLOUGH TAPE LEVEL. 

No. 158. 




P.:. JdIj I. 1893 

Insures accuracy in measurements with steel tapes. Above cut fui". 
Weight one ounce. It is used by clamping to the tape, about one foot from the 
handle, by means of the two springs shown, and can be attached and detached 
instantly. 

Price, $1.50. 



(a) THERMOMETERS. 

A full supply of thermometers, plain, maximum and minimum, and hygrome- 
ters kept in stock. 



NAUTICAL INSTRUMENTS. 
This catalogue does not contain our supply of nautical instruments, of which 
we keep in stock a number of the usual articles required by the navigator, partic- 
ularly in the line of ship's compasses and logs. In the near future a price list of 
these goods will be published by the Company, but for the present a mere reference 
to this branch of our work shall onlv be made here. 



INDEX. 



Parts I, II and III have numbered pages. Part IV has running numbers of 
articles and is not paged, and the index references are made accordingly. 

No. or Page. 

Address an instrument to the Company, how to 53 

Adjusting Booro, the 3 

Adjustments, charges for 52 

collimators for 3 

of the dumpy level 64 

of the plane-table alidade 70 

of the transit 54 

of the Y- level 60 

Agate fittings for Y- level Part IV, No. 22, 40 

Agate setting for needle 19 

Air pump for testing aneroids 4 

Airy eye-piece, the 29 

Alidade, adjustment of the 70 

' ' the plane-table 43 

" of aluminium 45 

Alt-Azimuth instrument Part IV, Nos. 38-40 

Aluminium alloys 44 

adaptability of 3, 43, 46, 93 

" alidade 45 

" instruments, stability of 44 

1 ' levels 45 

" solar attachments 45 

' ' transits 45 

Anemometers Part IV, No. 127a 

Aneroid, the Goldschmid Part IV, No. 121a, 96 

Angle mirrors Part IV, No. 113a 

Artificial horizons Part IV, Nos. 114-115 

Axes of transit telescopes 21 

Balsam used in lenses 33 

Barograph (self-registering aneroid) 97 

Barometers, Aneroid Part IV, No. 121a 

' ' Goldschmid Aneroid 96 

Bell metal, use of : 38, 45 

Bending of plates and centers 48 

Bessel's spheroid, elements of 98 

Careless handling of instruments 46 

Care of instruments 46 

Case, the instrument 34, 40, 94 

Centering apparatus, the 3 

Centering the field of view 59 



Center pin for needle, adjusting 19, 49 

Centers, bending of 48 

1 ' length of 15 

" of dumpy level 41 

of Y- level 36 

' ' or vertical axis, the 14 

Chain pins Part IV, No. 72 

Chains, Surveyor's Part IT, Nos . 60-71 

Chromatic aberration, test for 67 

Circle, horizontal 16 

" vertical 21 

" " adjustment of 59 

Clamp Screws IS, 94 

Clarke's Spheroid, elements of 98 

Clinometers Part TV, Nos. 54-55 

Cloth-finish, dumpy level 41 

Y-level 39 

" telescope standards 21 

Clothing, influence on needle 49 

Collars of the Y-level 38 

' ' the inequality of 38, 63 

Collar test, the 63 

Collimation, line of 56 

Collimators, the mural 3 

Compass, graduation of the 19 

needle 18, 93 

pocket Part IV, Nos. 4S-49 

' ' prismatic Part IT, No. 47 

' ' repairs to 52 

" Surveyors' Part IV, Nos. 45-46 

Conical bearings of telescope axis 21 

Construction of instruments 93 

Correspondence regarding repairs . 51 

Cost of repairs 52 

Cross-hairs, adjustment of 56, 62, 65 

' ' frame for 30 

" glass diaphragm for 31 

1 ' how to replace 50 

Crown glass in lenses -7 

Definition of telescopes 3S, 66 

Dividing engine, large circular 3 

" " linear -1 

Directors of the A. Lietz Company VII 

Drawing instruments Part IV, No. 129d 

Dumpy level, the -40 

" " adjustment of 64 

" " centers of -41 

" cloth-finished 41 

" " of aluminium -45 

" price of Part IV, Nos. 23-24 

Dust caps 1-4 



Eccentricity 15 

" graphical determination of 95 

Emery, danger of using 48 

Equatorial Part IV, No. 36 

Equatorial mountings Part IV, No. J 29b 

Establishment, description of the A. Lietz . . . . . 2 

Eye-piece, the 28 

' ' care of 50 

the Airy.... 29 

- " the erect 29 

' ' the Huy ghens 29 

' ' the inverting 29 

the Kellner , 28 

" the negative 29 

' ' the positive 29 

' ' the Ramsden 28 

the Steinheil 28 

' ' the terrestrial 29 

Field glasses Part IV, No. 121b 

Finish of instruments, the . . 34, 39, 94 

Flatness of field, test for ? 67 

Flint glass in lenses -. 27 

Focal length, apparatus for determining the 69 

Focal length of objectives 28 

Foundry, the 2 

Fretting of working parts 47 

Cxlass diaphragms for cross-lines 31 

Goldschmid Aneroid, the 96 

Gradienter, observing horizontal distances by the. 22 

Gradienter, the 21 

Graduation, accuracy of lines 91 

" of compass 19 

' ' on solid silver 16 

' ' plate, the 15 

' ' room, the . . . .' 3 

tester, the 3 

Heliotropes Part IV, Nos. 116-121 

How to tell a good surveying instrument 91 

Huyghens eye-piece, the 29 

Illumination of cross-hairs 30 

Importations 4 

Incorporation of the A. Lietz Company VII 

*' Irrigation Age, " extract from 5 

Jena Glass Works 23 

Kellner eye-piece, the 28 

Lamps, illuminating Part IV, Nos. 56-59 

Latitude coefficients, table of : 109 

' ' length of one minute of 100 



Lenses, balsaming of 33 

centering of 28, 33, 50, 62 

' ' cleaning of 50 

' ' imported , 4 

' ' staining of 50 

' ' transit telescope 23 

Level, Dumpy (see D) 40 

" German Pocket Part IV, Nos. 25-28, 41 

" Hand Part IV, No. 50 

' ' instrument 36 

" McCullough tape Part IV, No. 158 

" Millwright, Carpenter's and Machinist's Part IV, Nos. 126-127 

" Eeflecting (Abneys) Part IV, Nos. 52-53 

" Kod Part IV, No. Ill 

' ' Screws 13 

' ' sensitiveness of bubble 22, 36, 52 

tester 4, 23 

Y -Level, the 36 

" adjustments 60 

" agate fittings 40 

' ( aluminium '. 45 

' ' center of 36 

' ' cloth-finish of e 39 

collars of 38 

' ' curvature of tube 36 

' ' magnifying power of 37 

' ' packing in case 40 

' ' precision 40 

' ' price of Part IV, No. 22 

' ' repairs to 52 

Lifting arrangement of needle , 19 

Longitude, how to rind the length of one minute of 98 

Lubrication of certain parts 48 

Magnetic attraction in clothing 49 

Magnetic needle 18, 93 

Magnetic variation, to set off the 20 

Magnifiers, Pocket Part IV, No. 129c 

Magnifying power of telescopes 32, 37 

"to find the 68 

Marking tools Part IV, No. 73 

Mechanical devices made 4 

Meridian instruments Part IV, No. 37 

Metal tester, the 4 

Microscopes Part IV, No. 129a 

Models made, mechanical 4 

Nautical Department, the 4 

Mile, length of , 100 



Needle, the magnetic +,*..* 18, 93 

' ' center-cap of 19 

' ' center-pin of 19 

" lifting arrangement of , 19 

" to restore magnetism of 49 

" to preserve sensitiveness of 48 

Nonius, the . , 16 

Object glass, the t 27 

Objectives, focal length of 28 

Odometers Part IV, No. 122 

Optical axis, coincidence of 28, 33, 50, 62 

Orthoscopic eye-piece 28 

Packing transit in case 34 

' ' level in case 40 

Parallax, adjustment of 54, 63 

Parallelism of collars in Y-level 61 

" " telescope in Y-level 60 

Pedometers Part IV, Nos. 123-125 

Plane-table, the „ 43 

" adjustment of alidade 70 

price of Part IV, No. 29 

Planimeters Part IV, No. 44 

Plates, bending of 48 

' ' horizontal 15 

' ' levels for 54 

Plumb-bobs .Part IV, No. 59a 

Plumbing arrangement 14 

Poles, Sight Part IV, Nos. 32-34 

Prices of Dumpy level " " 23-24 

' ' German level " " 25-28 

Y-level " No. 22 

Plane-table '< " 29 

" Theodolite . " " 5 

" Transit, complete " Nos. 3-4 

" " compound mining and solar " " 18-21 

" " mining " " 10-11 

" " mountain and mining " " 6-9 

" " plain " No. 1 

" " with telescope level " " 2 

" " simplified " Nos. 12-17 

Protection from rain 47 

" " sun 47 

Protractors Part IV, No. 129e 

Ramsden eye-piece, the 28 

Reflecting circles Part IV, Nos. 42-43 

Refraction correction table 110 

Refraction table, mean 105 

Remarks on instruments 42, 91 



Repairs <--.... 51 

' ' cost of 52 

' ' what to send . . 52 

Eight-angles, arrangement for laying off 34 

Eods, level Part IV, No. 31 

" sight Part IV, Nos. 32-34 

" Stadia (flexible) Part IV, No. 35 

Rules, Slide Part IV, No. 157 

Saccharimeter Part IV, No. 128 

Saegmitller Solar Attachment 34, 45, 101 

Scales Part IV, Nos. 130-153 

Screws, overstraining 47 

Seismograph Part IV, No. 28a 

Sextants Part IV, Nos. 1 12-1 1 3 

Shake in the slide ,. 30 

tripod: 48 

Shifting center 14, 94 

Shipping an instrument II, 53 

Shoes, tripod 35 

Silver, graduation on solid 16 

Simplified transits Part IV, Nos. 12-17 

Size of transits Part IV and 34 

" levels . . . Part IV 

Slide, the 30, 47 

' ' protector, the 30, 39 

" rules Part IV, No. 157 

" scale, the logarithmic 84 

Solar attachment 34 

Solar attachment of aluminium 45 

Solar attachment, Saegmtiller 34, 45, 101 

Spectroscopes Part IV, No. 129 

Spherical aberration, test for 66 

Spheroid, elements of the terrestrial 98 

Spider web, the 30 

Spirit levels (vials) - 4, 22 

" " importance of sensitive 22 

Stability of instruments 13, 93 

" aluminium instruments 44, 93 

Stadia hairs, fixed 31, 40, 41 

" " adjustable 31 

Stadia reduction tables 80 

' ' Surveying, treatise on 74 

Standards, the 20, 94 

unequal expansion in 21 

Star-shaped casting for leveling screws 13, 94 

Station-pointer Part IV, No. 129e 

Steel center in Y-level 36,, 45 

Steinheil eye-piece, the ! 28 

Straight-edges Part IV, No. 156 

Sun-shade, the 30, 39 

Surveying instrument, how to tell a good 91 



Tables, mean refraction 105 

' ' of latitude coefficients 109 

" refraction correction 110 

' ' stadia reduction 80 

Tangent screws 18, 94 

Tape lines (steel and metallic) Part IV, Nos. 74-99 

ribbons Part IV, Nos. 100-110 

Telescope, accurate balance of 32 

' ' bearings, adjustment of 55 

' ' cleaning of 49 

' ' definition of 66 

" finding the magnifying power of a 68 

" general remarks on 32, 91 

level 37 

" " adjustment of 58, 62 

' ' magnifying power of 32 

' ' reversibility of transit 32 

' ' test of 66 

" transit 23 

" " adjustment of 55 

Testimonials (on first leaves of Manual). 

Theodolite, description of 10 

" highest grade 43 

" " with micrometers Part IV, No. 41 

" price of Part IV, No. 5 

' ' size of Part IV, No . 5 

Three-leveling-screw arrangement 14 

Thermometers Part IV, No. 158a 

Transit, adjustments of the 54-60 

' ' aluminium 45 

1 ' centers of 14 

' ' description of 10 

' ' packing in case 34 

" price of Part IV, Nos. 1-21 

' ' repairs to 52 

simplified Part IV, Nos. 12-17 

sizes of Part IV, Nos. 1-21 

Triangles Part IV, Nos. 154-155 

Tripod connection 1 1, 94 

" coupling, the new Lietz 12 

' ' shake in 48 

' ' split leg 35 

Variation, setting off the magnetic 20 

" plate 19 

Vernier, the 16 

• ' position of 17, 93 

' ' protected by glass 17 

" shades 17 

' ' theory of the 17 



Ylll 

Vertical arc 21 

" " adjustment of the 59 

Werner, Peter 17 

Workshop, description of the 2 

Y-level (see level) 36 

Zero of vertical arc 59 



LIST OF ILLUSTRATIONS. 



PART I. 

Plate 1. Interior View of Workshop. 

2. Interior of Graduating and Adjusting Room. 

3. Circular Dividing Engine. 

4. Centering Apparatus for Testing Graduations. 

4. Linear Dividing Engine. 

5. Level Tester. 

5. Apparatus for Testing Magnetic Influence. 

6. Mural Collimator Apparatus. 

PART II. 

Page 12. The Lietz Tripod Coupling. 

" 69. Apparatus for Measuring the Focal Length. 

PART III. 

Figure 1. Diagram of Optical Features in Telescope. 

Stadia Surveying, page 75. 
Figure 2. Diagram showing Stadia Reductions. 

Stadia Surveying, page 76. 
Figures 1-5. Logarithmic Scales. 

"Remarks on the Principle of the Logarithmic Slide Scale," page 86. 
Figures A, B and C. Magnified Graduation Lines. 

"How to Tell a Good Surveying Instrument," page 91. 
Graphical Determination of Eccentricity. 

"How to Tell a Good Surveying Instrument,'''' page 95. 
Figures 1, 2 and 3. Goldschmid Aneroid Barometer. 
"Goldschmid Aneroid," page 96. 
Saegm idler Solar Attachment. 

"The Saegmilller Solar Attachment," page 103. 
Spherical Triangle. 

"The Saegmnller Solar Attachment," page 104. 

PART IV. 

Plate 1. Plain Transit. 

2. Transit, with Telescope Level. 

3. Complete Engineer's Transit. 

4. Complete Engineer's Transit. 

5. Complete Transit-Theodolite. 

6. Complete Mountain and Mining Transit. 

7. Simplified Transits (Compasses). 

8. Simplified Transits. 



" 9. Compound Mining find Solar Instrument. 
•' 10. Compound Mining and Solar Instrument. 
" 11. Compound Mining and Solar Transit. 
' : 12. Compound Mining and Solar Transit. 
" 13. Y-Level. 
' ' 14. Dumpy Levels. 

Section of German Level Telescope. 
" 15. German Levels. 

Complete Pocket Surveying Instrument. 
No. 28a. Seismograph. 
Plate 16. Plane-table. 

" 17. Leveling Rods and Range-poles. 
No. 36. Equatorial. 

" 37. Meridian Instrument. 
Nos. 38-40. Alt- Azimuth Instruments. 
No. 41. Theodolite with Micrometers. 
Nos. 42, 43. Reflecting Circles. 
No. 44. Amsler's Planimeter. 
Nos. 45-47. Surveyor's Compasses. 
No. 50. Lock's Hand Level. 
" 54. Atwood's Clinometer. 
" 100. Hodgman's Steel Ribbon. 
'■ 121a. Altitude Barometer. 
" 121b. Field Glasses. 
" 129c. Protractor. 
" 158. McCullough Tape Level. 



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